1 00:00:00,000 --> 00:00:02,000 So, I want to start out with 2 00:00:02,000 --> 00:00:04,000 this beautiful picture from my childhood. 3 00:00:04,000 --> 00:00:06,000 I love the science fiction movies. 4 00:00:06,000 --> 00:00:08,000 Here it is: "This Island Earth." 5 00:00:08,000 --> 00:00:10,000 And leave it to Hollywood to get it just right. 6 00:00:10,000 --> 00:00:12,000 Two-and-a-half years in the making. 7 00:00:12,000 --> 00:00:15,000 (Laughter) 8 00:00:15,000 --> 00:00:18,000 I mean, even the creationists give us 6,000, 9 00:00:18,000 --> 00:00:20,000 but Hollywood goes to the chase. 10 00:00:20,000 --> 00:00:24,000 And in this movie, we see what we think is out there: 11 00:00:24,000 --> 00:00:27,000 flying saucers and aliens. 12 00:00:27,000 --> 00:00:30,000 Every world has an alien, and every alien world has a flying saucer, 13 00:00:30,000 --> 00:00:34,000 and they move about with great speed. Aliens. 14 00:00:35,000 --> 00:00:38,000 Well, Don Brownlee, my friend, and I finally got to the point 15 00:00:38,000 --> 00:00:41,000 where we got tired of turning on the TV 16 00:00:41,000 --> 00:00:44,000 and seeing the spaceships and seeing the aliens every night, 17 00:00:44,000 --> 00:00:47,000 and tried to write a counter-argument to it, 18 00:00:47,000 --> 00:00:51,000 and put out what does it really take for an Earth to be habitable, 19 00:00:51,000 --> 00:00:53,000 for a planet to be an Earth, to have a place 20 00:00:53,000 --> 00:00:56,000 where you could probably get not just life, but complexity, 21 00:00:56,000 --> 00:00:58,000 which requires a huge amount of evolution, 22 00:00:58,000 --> 00:01:01,000 and therefore constancy of conditions. 23 00:01:01,000 --> 00:01:04,000 So, in 2000 we wrote "Rare Earth." In 2003, we then asked, 24 00:01:04,000 --> 00:01:09,000 let's not think about where Earths are in space, but how long has Earth been Earth? 25 00:01:09,000 --> 00:01:11,000 If you go back two billion years, 26 00:01:11,000 --> 00:01:13,000 you're not on an Earth-like planet any more. 27 00:01:13,000 --> 00:01:17,000 What we call an Earth-like planet is actually a very short interval of time. 28 00:01:17,000 --> 00:01:19,000 Well, "Rare Earth" actually 29 00:01:19,000 --> 00:01:22,000 taught me an awful lot about meeting the public. 30 00:01:22,000 --> 00:01:25,000 Right after, I got an invitation to go to a science fiction convention, 31 00:01:25,000 --> 00:01:28,000 and with all great earnestness walked in. 32 00:01:28,000 --> 00:01:30,000 David Brin was going to debate me on this, 33 00:01:30,000 --> 00:01:34,000 and as I walked in, the crowd of a hundred started booing lustily. 34 00:01:34,000 --> 00:01:37,000 I had a girl who came up who said, "My dad says you're the devil." 35 00:01:37,000 --> 00:01:41,000 You cannot take people's aliens away from them 36 00:01:41,000 --> 00:01:45,000 and expect to be anybody's friends. 37 00:01:45,000 --> 00:01:47,000 Well, the second part of that, soon after -- 38 00:01:47,000 --> 00:01:50,000 and I was talking to Paul Allen; I saw him in the audience, 39 00:01:50,000 --> 00:01:52,000 and I handed him a copy of "Rare Earth." 40 00:01:52,000 --> 00:01:56,000 And Jill Tarter was there, and she turned to me, 41 00:01:56,000 --> 00:01:59,000 and she looked at me just like that girl in "The Exorcist." 42 00:01:59,000 --> 00:02:01,000 It was, "It burns! It burns!" 43 00:02:01,000 --> 00:02:03,000 Because SETI doesn't want to hear this. 44 00:02:03,000 --> 00:02:06,000 SETI wants there to be stuff out there. 45 00:02:06,000 --> 00:02:09,000 I really applaud the SETI efforts, but we have not heard anything yet. 46 00:02:09,000 --> 00:02:11,000 And I really do think we have to start thinking 47 00:02:11,000 --> 00:02:14,000 about what's a good planet and what isn't. 48 00:02:14,000 --> 00:02:17,000 Now, I throw this slide up because it indicates to me that, 49 00:02:17,000 --> 00:02:21,000 even if SETI does hear something, can we figure out what they said? 50 00:02:21,000 --> 00:02:23,000 Because this was a slide that was passed 51 00:02:23,000 --> 00:02:27,000 between the two major intelligences on Earth -- a Mac to a PC -- 52 00:02:27,000 --> 00:02:30,000 and it can't even get the letters right -- 53 00:02:30,000 --> 00:02:32,000 (Laughter) 54 00:02:32,000 --> 00:02:34,000 -- so how are we going to talk to the aliens? 55 00:02:34,000 --> 00:02:37,000 And if they're 50 light years away, and we call them up, 56 00:02:37,000 --> 00:02:39,000 and you blah, blah, blah, blah, blah, 57 00:02:39,000 --> 00:02:42,000 and then 50 years later it comes back and they say, Please repeat? 58 00:02:42,000 --> 00:02:44,000 I mean, there we are. 59 00:02:44,000 --> 00:02:47,000 Our planet is a good planet because it can keep water. 60 00:02:47,000 --> 00:02:51,000 Mars is a bad planet, but it's still good enough for us to go there 61 00:02:51,000 --> 00:02:53,000 and to live on its surface if we're protected. 62 00:02:53,000 --> 00:02:56,000 But Venus is a very bad -- the worst -- planet. 63 00:02:56,000 --> 00:02:59,000 Even though it's Earth-like, and even though early in its history 64 00:02:59,000 --> 00:03:02,000 it may very well have harbored Earth-like life, 65 00:03:02,000 --> 00:03:05,000 it soon succumbed to runaway greenhouse -- 66 00:03:05,000 --> 00:03:07,000 that's an 800 degrees [Fahrenheit] surface -- 67 00:03:07,000 --> 00:03:10,000 because of rampant carbon dioxide. 68 00:03:10,000 --> 00:03:13,000 Well, we know from astrobiology that we can really now predict 69 00:03:13,000 --> 00:03:16,000 what's going to happen to our particular planet. 70 00:03:16,000 --> 00:03:19,000 We are right now in the beautiful Oreo 71 00:03:19,000 --> 00:03:22,000 of existence -- of at least life on Planet Earth -- 72 00:03:22,000 --> 00:03:25,000 following the first horrible microbial age. 73 00:03:25,000 --> 00:03:28,000 In the Cambrian explosion, life emerged from the swamps, 74 00:03:28,000 --> 00:03:30,000 complexity arose, 75 00:03:30,000 --> 00:03:33,000 and from what we can tell, we're halfway through. 76 00:03:33,000 --> 00:03:36,000 We have as much time for animals to exist on this planet 77 00:03:36,000 --> 00:03:38,000 as they have been here now, 78 00:03:38,000 --> 00:03:40,000 till we hit the second microbial age. 79 00:03:40,000 --> 00:03:42,000 And that will happen, paradoxically -- 80 00:03:42,000 --> 00:03:44,000 everything you hear about global warming -- 81 00:03:44,000 --> 00:03:47,000 when we hit CO2 down to 10 parts per million, 82 00:03:47,000 --> 00:03:49,000 we are no longer going to have to have plants 83 00:03:49,000 --> 00:03:53,000 that are allowed to have any photosynthesis, and there go animals. 84 00:03:53,000 --> 00:03:55,000 So, after that we probably have seven billion years. 85 00:03:55,000 --> 00:03:58,000 The Sun increases in its intensity, in its brightness, 86 00:03:58,000 --> 00:04:03,000 and finally, at about 12 billion years after it first started, 87 00:04:03,000 --> 00:04:06,000 the Earth is consumed by a large Sun, 88 00:04:06,000 --> 00:04:09,000 and this is what's left. 89 00:04:09,000 --> 00:04:13,000 So, a planet like us is going to have an age and an old age, 90 00:04:13,000 --> 00:04:17,000 and we are in its golden summer age right now. 91 00:04:17,000 --> 00:04:19,000 But there's two fates to everything, isn't there? 92 00:04:19,000 --> 00:04:22,000 Now, a lot of you are going to die of old age, 93 00:04:22,000 --> 00:04:25,000 but some of you, horribly enough, are going to die in an accident. 94 00:04:25,000 --> 00:04:27,000 And that's the fate of a planet, too. 95 00:04:27,000 --> 00:04:31,000 Earth, if we're lucky enough -- if it doesn't get hit by a Hale-Bopp, 96 00:04:31,000 --> 00:04:35,000 or gets blasted by some supernova nearby 97 00:04:35,000 --> 00:04:38,000 in the next seven billion years -- we'll find under your feet. 98 00:04:38,000 --> 00:04:40,000 But what about accidental death? 99 00:04:40,000 --> 00:04:42,000 Well, paleontologists for the last 200 years 100 00:04:42,000 --> 00:04:44,000 have been charting death. It's strange -- 101 00:04:44,000 --> 00:04:47,000 extinction as a concept wasn't even thought about 102 00:04:47,000 --> 00:04:50,000 until Baron Cuvier in France found this first mastodon. 103 00:04:50,000 --> 00:04:52,000 He couldn't match it up to any bones on the planet, 104 00:04:52,000 --> 00:04:54,000 and he said, Aha! It's extinct. 105 00:04:54,000 --> 00:04:57,000 And very soon after, the fossil record started yielding 106 00:04:57,000 --> 00:05:00,000 a very good idea of how many plants and animals there have been 107 00:05:00,000 --> 00:05:02,000 since complex life really began to leave 108 00:05:02,000 --> 00:05:05,000 a very interesting fossil record. 109 00:05:05,000 --> 00:05:08,000 In that complex record of fossils, 110 00:05:08,000 --> 00:05:10,000 there were times when lots of stuff 111 00:05:10,000 --> 00:05:12,000 seemed to be dying out very quickly, 112 00:05:12,000 --> 00:05:14,000 and the father/mother geologists 113 00:05:14,000 --> 00:05:16,000 called these "mass extinctions." 114 00:05:16,000 --> 00:05:18,000 All along it was thought to be either an act of God 115 00:05:18,000 --> 00:05:20,000 or perhaps long, slow climate change, 116 00:05:20,000 --> 00:05:22,000 and that really changed in 1980, 117 00:05:22,000 --> 00:05:25,000 in this rocky outcrop near Gubbio, 118 00:05:25,000 --> 00:05:28,000 where Walter Alvarez, trying to figure out 119 00:05:28,000 --> 00:05:31,000 what was the time difference between these white rocks, 120 00:05:31,000 --> 00:05:33,000 which held creatures of the Cretaceous period, 121 00:05:33,000 --> 00:05:35,000 and the pink rocks above, which held Tertiary fossils. 122 00:05:35,000 --> 00:05:39,000 How long did it take to go from one system to the next? 123 00:05:39,000 --> 00:05:41,000 And what they found was something unexpected. 124 00:05:41,000 --> 00:05:44,000 They found in this gap, in between, a very thin clay layer, 125 00:05:44,000 --> 00:05:47,000 and that clay layer -- this very thin red layer here -- 126 00:05:47,000 --> 00:05:49,000 is filled with iridium. 127 00:05:49,000 --> 00:05:52,000 And not just iridium; it's filled with glassy spherules, 128 00:05:52,000 --> 00:05:54,000 and it's filled with quartz grains 129 00:05:54,000 --> 00:05:58,000 that have been subjected to enormous pressure: shock quartz. 130 00:05:58,000 --> 00:06:00,000 Now, in this slide the white is chalk, 131 00:06:00,000 --> 00:06:03,000 and this chalk was deposited in a warm ocean. 132 00:06:03,000 --> 00:06:05,000 The chalk itself's composed by plankton 133 00:06:05,000 --> 00:06:09,000 which has fallen down from the sea surface onto the sea floor, 134 00:06:09,000 --> 00:06:12,000 so that 90 percent of the sediment here is skeleton of living stuff, 135 00:06:12,000 --> 00:06:14,000 and then you have that millimeter-thick red layer, 136 00:06:14,000 --> 00:06:16,000 and then you have black rock. 137 00:06:16,000 --> 00:06:19,000 And the black rock is the sediment on the sea bottom 138 00:06:19,000 --> 00:06:21,000 in the absence of plankton. 139 00:06:21,000 --> 00:06:25,000 And that's what happens in an asteroid catastrophe, 140 00:06:25,000 --> 00:06:28,000 because that's what this was, of course. This is the famous K-T. 141 00:06:28,000 --> 00:06:30,000 A 10-kilometer body hit the planet. 142 00:06:30,000 --> 00:06:34,000 The effects of it spread this very thin impact layer all over the planet, 143 00:06:34,000 --> 00:06:37,000 and we had very quickly the death of the dinosaurs, 144 00:06:37,000 --> 00:06:39,000 the death of these beautiful ammonites, 145 00:06:39,000 --> 00:06:41,000 Leconteiceras here, and Celaeceras over here, 146 00:06:41,000 --> 00:06:43,000 and so much else. 147 00:06:43,000 --> 00:06:45,000 I mean, it must be true, 148 00:06:45,000 --> 00:06:48,000 because we've had two Hollywood blockbusters since that time, 149 00:06:48,000 --> 00:06:51,000 and this paradigm, from 1980 to about 2000, 150 00:06:51,000 --> 00:06:56,000 totally changed how we geologists thought about catastrophes. 151 00:06:56,000 --> 00:06:59,000 Prior to that, uniformitarianism was the dominant paradigm: 152 00:06:59,000 --> 00:07:02,000 the fact that if anything happens on the planet in the past, 153 00:07:02,000 --> 00:07:06,000 there are present-day processes that will explain it. 154 00:07:06,000 --> 00:07:09,000 But we haven't witnessed a big asteroid impact, 155 00:07:09,000 --> 00:07:11,000 so this is a type of neo-catastrophism, 156 00:07:11,000 --> 00:07:14,000 and it took about 20 years for the scientific establishment 157 00:07:14,000 --> 00:07:16,000 to finally come to grips: yes, we were hit; 158 00:07:16,000 --> 00:07:20,000 and yes, the effects of that hit caused a major mass extinction. 159 00:07:21,000 --> 00:07:23,000 Well, there are five major mass extinctions 160 00:07:23,000 --> 00:07:26,000 over the last 500 million years, called the Big Five. 161 00:07:26,000 --> 00:07:29,000 They range from 450 million years ago 162 00:07:29,000 --> 00:07:31,000 to the last, the K-T, number four, 163 00:07:31,000 --> 00:07:35,000 but the biggest of all was the P, or the Permian extinction, 164 00:07:35,000 --> 00:07:37,000 sometimes called the mother of all mass extinctions. 165 00:07:37,000 --> 00:07:40,000 And every one of these has been subsequently blamed 166 00:07:40,000 --> 00:07:42,000 on large-body impact. 167 00:07:42,000 --> 00:07:44,000 But is this true? 168 00:07:45,000 --> 00:07:48,000 The most recent, the Permian, was thought to have been an impact 169 00:07:48,000 --> 00:07:50,000 because of this beautiful structure on the right. 170 00:07:50,000 --> 00:07:53,000 This is a Buckminsterfullerene, a carbon-60. 171 00:07:53,000 --> 00:07:56,000 Because it looks like those terrible geodesic domes 172 00:07:56,000 --> 00:07:58,000 of my late beloved '60s, 173 00:07:58,000 --> 00:08:00,000 they're called "buckyballs." 174 00:08:00,000 --> 00:08:02,000 This evidence was used to suggest 175 00:08:02,000 --> 00:08:06,000 that at the end of the Permian, 250 million years ago, a comet hit us. 176 00:08:06,000 --> 00:08:09,000 And when the comet hits, the pressure produces the buckyballs, 177 00:08:09,000 --> 00:08:11,000 and it captures bits of the comet. 178 00:08:11,000 --> 00:08:15,000 Helium-3: very rare on the surface of the Earth, very common in space. 179 00:08:16,000 --> 00:08:18,000 But is this true? 180 00:08:18,000 --> 00:08:22,000 In 1990, working on the K-T extinction for 10 years, 181 00:08:22,000 --> 00:08:25,000 I moved to South Africa to begin work twice a year 182 00:08:25,000 --> 00:08:27,000 in the great Karoo desert. 183 00:08:27,000 --> 00:08:30,000 I was so lucky to watch the change of that South Africa 184 00:08:30,000 --> 00:08:33,000 into the new South Africa as I went year by year. 185 00:08:33,000 --> 00:08:35,000 And I worked on this Permian extinction, 186 00:08:35,000 --> 00:08:38,000 camping by this Boer graveyard for months at a time. 187 00:08:38,000 --> 00:08:41,000 And the fossils are extraordinary. 188 00:08:41,000 --> 00:08:43,000 You know, you're gazing upon your very distant ancestors. 189 00:08:43,000 --> 00:08:45,000 These are mammal-like reptiles. 190 00:08:45,000 --> 00:08:48,000 They are culturally invisible. We do not make movies about these. 191 00:08:48,000 --> 00:08:50,000 This is a Gorgonopsian, or a Gorgon. 192 00:08:50,000 --> 00:08:54,000 That's an 18-inch long skull of an animal 193 00:08:54,000 --> 00:08:58,000 that was probably seven or eight feet, sprawled like a lizard, 194 00:08:58,000 --> 00:09:00,000 probably had a head like a lion. 195 00:09:00,000 --> 00:09:02,000 This is the top carnivore, the T-Rex of its time. 196 00:09:02,000 --> 00:09:04,000 But there's lots of stuff. 197 00:09:04,000 --> 00:09:06,000 This is my poor son, Patrick. 198 00:09:06,000 --> 00:09:07,000 (Laughter) 199 00:09:07,000 --> 00:09:10,000 This is called paleontological child abuse. 200 00:09:10,000 --> 00:09:12,000 Hold still, you're the scale. 201 00:09:12,000 --> 00:09:17,000 (Laughter) 202 00:09:18,000 --> 00:09:21,000 There was big stuff back then. 203 00:09:21,000 --> 00:09:24,000 Fifty-five species of mammal-like reptiles. 204 00:09:24,000 --> 00:09:27,000 The age of mammals had well and truly started 205 00:09:27,000 --> 00:09:29,000 250 million years ago ... 206 00:09:29,000 --> 00:09:32,000 ... and then a catastrophe happened. 207 00:09:32,000 --> 00:09:34,000 And what happens next is the age of dinosaurs. 208 00:09:34,000 --> 00:09:38,000 It was all a mistake; it should have never happened. But it did. 209 00:09:38,000 --> 00:09:40,000 Now, luckily, 210 00:09:40,000 --> 00:09:43,000 this Thrinaxodon, the size of a robin egg here: 211 00:09:43,000 --> 00:09:46,000 this is a skull I've discovered just before taking this picture -- 212 00:09:46,000 --> 00:09:48,000 there's a pen for scale; it's really tiny -- 213 00:09:48,000 --> 00:09:52,000 this is in the Lower Triassic, after the mass extinction has finished. 214 00:09:52,000 --> 00:09:55,000 You can see the eye socket and you can see the little teeth in the front. 215 00:09:55,000 --> 00:10:00,000 If that does not survive, I'm not the thing giving this talk. 216 00:10:00,000 --> 00:10:04,000 Something else is, because if that doesn't survive, we are not here; 217 00:10:04,000 --> 00:10:08,000 there are no mammals. It's that close; one species ekes through. 218 00:10:08,000 --> 00:10:11,000 Well, can we say anything about the pattern of who survives and who doesn't? 219 00:10:11,000 --> 00:10:13,000 Here's sort of the end of that 10 years of work. 220 00:10:13,000 --> 00:10:16,000 The ranges of stuff -- the red line is the mass extinction. 221 00:10:16,000 --> 00:10:18,000 But we've got survivors and things that get through, 222 00:10:18,000 --> 00:10:22,000 and it turns out the things that get through preferentially are cold bloods. 223 00:10:22,000 --> 00:10:26,000 Warm-blooded animals take a huge hit at this time. 224 00:10:27,000 --> 00:10:29,000 The survivors that do get through 225 00:10:29,000 --> 00:10:32,000 produce this world of crocodile-like creatures. 226 00:10:32,000 --> 00:10:36,000 There's no dinosaurs yet; just this slow, saurian, scaly, nasty, 227 00:10:36,000 --> 00:10:41,000 swampy place with a couple of tiny mammals hiding in the fringes. 228 00:10:41,000 --> 00:10:44,000 And there they would hide for 160 million years, 229 00:10:44,000 --> 00:10:47,000 until liberated by that K-T asteroid. 230 00:10:47,000 --> 00:10:49,000 So, if not impact, what? 231 00:10:49,000 --> 00:10:53,000 And the what, I think, is that we returned, over and over again, 232 00:10:53,000 --> 00:10:56,000 to the Pre-Cambrian world, that first microbial age, 233 00:10:56,000 --> 00:10:58,000 and the microbes are still out there. 234 00:10:58,000 --> 00:11:00,000 They hate we animals. 235 00:11:00,000 --> 00:11:02,000 They really want their world back. 236 00:11:02,000 --> 00:11:06,000 And they've tried over and over and over again. 237 00:11:06,000 --> 00:11:09,000 This suggests to me that life causing these mass extinctions 238 00:11:09,000 --> 00:11:12,000 because it did is inherently anti-Gaian. 239 00:11:12,000 --> 00:11:17,000 This whole Gaia idea, that life makes the world better for itself -- 240 00:11:17,000 --> 00:11:21,000 anybody been on a freeway on a Friday afternoon in Los Angeles 241 00:11:21,000 --> 00:11:23,000 believing in the Gaia theory? No. 242 00:11:23,000 --> 00:11:26,000 So, I really suspect there's an alternative, 243 00:11:26,000 --> 00:11:28,000 and that life does actually try to do itself in -- 244 00:11:28,000 --> 00:11:30,000 not consciously, but just because it does. 245 00:11:30,000 --> 00:11:34,000 And here's the weapon, it seems, that it did so over the last 500 million years. 246 00:11:34,000 --> 00:11:37,000 There are microbes which, through their metabolism, 247 00:11:37,000 --> 00:11:39,000 produce hydrogen sulfide, 248 00:11:39,000 --> 00:11:42,000 and they do so in large amounts. 249 00:11:42,000 --> 00:11:45,000 Hydrogen sulfide is very fatal to we humans. 250 00:11:45,000 --> 00:11:49,000 As small as 200 parts per million will kill you. 251 00:11:51,000 --> 00:11:55,000 You only have to go to the Black Sea and a few other places -- some lakes -- 252 00:11:55,000 --> 00:11:59,000 and get down, and you'll find that the water itself turns purple. 253 00:11:59,000 --> 00:12:02,000 It turns purple from the presence of numerous microbes 254 00:12:02,000 --> 00:12:05,000 which have to have sunlight and have to have hydrogen sulfide, 255 00:12:05,000 --> 00:12:09,000 and we can detect their presence today -- we can see them -- 256 00:12:09,000 --> 00:12:11,000 but we can also detect their presence in the past. 257 00:12:11,000 --> 00:12:13,000 And the last three years have seen 258 00:12:13,000 --> 00:12:16,000 an enormous breakthrough in a brand-new field. 259 00:12:16,000 --> 00:12:18,000 I am almost extinct -- 260 00:12:18,000 --> 00:12:20,000 I'm a paleontologist who collects fossils. 261 00:12:20,000 --> 00:12:23,000 But the new wave of paleontologists -- my graduate students -- 262 00:12:23,000 --> 00:12:25,000 collect biomarkers. 263 00:12:25,000 --> 00:12:29,000 They take the sediment itself, they extract the oil from it, 264 00:12:29,000 --> 00:12:31,000 and from that they can produce compounds 265 00:12:31,000 --> 00:12:35,000 which turn out to be very specific to particular microbial groups. 266 00:12:35,000 --> 00:12:39,000 It's because lipids are so tough, they can get preserved in sediment 267 00:12:39,000 --> 00:12:42,000 and last the hundreds of millions of years necessary, 268 00:12:42,000 --> 00:12:44,000 and be extracted and tell us who was there. 269 00:12:44,000 --> 00:12:47,000 And we know who was there. At the end of the Permian, 270 00:12:47,000 --> 00:12:49,000 at many of these mass extinction boundaries, 271 00:12:49,000 --> 00:12:53,000 this is what we find: isorenieratene. It's very specific. 272 00:12:53,000 --> 00:12:57,000 It can only occur if the surface of the ocean has no oxygen, 273 00:12:57,000 --> 00:13:00,000 and is totally saturated with hydrogen sulfide -- 274 00:13:00,000 --> 00:13:03,000 enough, for instance, to come out of solution. 275 00:13:03,000 --> 00:13:07,000 This led Lee Kump, and others from Penn State and my group, 276 00:13:07,000 --> 00:13:10,000 to propose what I call the Kump Hypothesis: 277 00:13:10,000 --> 00:13:13,000 many of the mass extinctions were caused by lowering oxygen, 278 00:13:13,000 --> 00:13:17,000 by high CO2. And the worst effect of global warming, it turns out: 279 00:13:17,000 --> 00:13:20,000 hydrogen sulfide being produced out of the oceans. 280 00:13:20,000 --> 00:13:22,000 Well, what's the source of this? 281 00:13:22,000 --> 00:13:26,000 In this particular case, the source over and over has been flood basalts. 282 00:13:26,000 --> 00:13:29,000 This is a view of the Earth now, if we extract a lot of it. 283 00:13:29,000 --> 00:13:31,000 And each of these looks like a hydrogen bomb; 284 00:13:31,000 --> 00:13:33,000 actually, the effects are even worse. 285 00:13:33,000 --> 00:13:36,000 This is when deep-Earth material comes to the surface, 286 00:13:36,000 --> 00:13:38,000 spreads out over the surface of the planet. 287 00:13:38,000 --> 00:13:41,000 Well, it's not the lava that kills anything, 288 00:13:41,000 --> 00:13:43,000 it's the carbon dioxide that comes out with it. 289 00:13:43,000 --> 00:13:46,000 This isn't Volvos; this is volcanoes. 290 00:13:46,000 --> 00:13:48,000 But carbon dioxide is carbon dioxide. 291 00:13:49,000 --> 00:13:52,000 So, these are new data Rob Berner and I -- from Yale -- put together, 292 00:13:52,000 --> 00:13:54,000 and what we try to do now is 293 00:13:54,000 --> 00:13:57,000 track the amount of carbon dioxide in the entire rock record -- 294 00:13:57,000 --> 00:14:00,000 and we can do this from a variety of means -- 295 00:14:00,000 --> 00:14:02,000 and put all the red lines here, 296 00:14:02,000 --> 00:14:05,000 when these -- what I call greenhouse mass extinctions -- took place. 297 00:14:05,000 --> 00:14:07,000 And there's two things that are really evident here to me, 298 00:14:07,000 --> 00:14:10,000 is that these extinctions take place when CO2 is going up. 299 00:14:10,000 --> 00:14:13,000 But the second thing that's not shown on here: 300 00:14:13,000 --> 00:14:16,000 the Earth has never had any ice on it 301 00:14:16,000 --> 00:14:20,000 when we've had 1,000 parts per million CO2. 302 00:14:20,000 --> 00:14:22,000 We are at 380 and climbing. 303 00:14:22,000 --> 00:14:25,000 We should be up to a thousand in three centuries at the most, 304 00:14:25,000 --> 00:14:29,000 but my friend David Battisti in Seattle says he thinks a 100 years. 305 00:14:29,000 --> 00:14:31,000 So, there goes the ice caps, 306 00:14:31,000 --> 00:14:35,000 and there comes 240 feet of sea level rise. 307 00:14:35,000 --> 00:14:37,000 I live in a view house now; 308 00:14:37,000 --> 00:14:39,000 I'm going to have waterfront. 309 00:14:39,000 --> 00:14:43,000 All right, what's the consequence? The oceans probably turn purple. 310 00:14:43,000 --> 00:14:46,000 And we think this is the reason that complexity took so long 311 00:14:46,000 --> 00:14:48,000 to take place on planet Earth. 312 00:14:48,000 --> 00:14:51,000 We had these hydrogen sulfide oceans for a very great long period. 313 00:14:51,000 --> 00:14:55,000 They stop complex life from existing. 314 00:14:55,000 --> 00:15:00,000 We know hydrogen sulfide is erupting presently a few places on the planet. 315 00:15:00,000 --> 00:15:04,000 And I throw this slide in -- this is me, actually, two months ago -- 316 00:15:04,000 --> 00:15:08,000 and I throw this slide in because here is my favorite animal, chambered nautilus. 317 00:15:08,000 --> 00:15:12,000 It's been on this planet since the animals first started -- 500 million years. 318 00:15:12,000 --> 00:15:15,000 This is a tracking experiment, and any of you scuba divers, 319 00:15:15,000 --> 00:15:18,000 if you want to get involved in one of the coolest projects ever, 320 00:15:18,000 --> 00:15:20,000 this is off the Great Barrier Reef. 321 00:15:20,000 --> 00:15:21,000 And as we speak now, 322 00:15:21,000 --> 00:15:24,000 these nautilus are tracking out their behaviors to us. 323 00:15:24,000 --> 00:15:28,000 But the thing about this is that every once in a while 324 00:15:28,000 --> 00:15:30,000 we divers can run into trouble, 325 00:15:30,000 --> 00:15:32,000 so I'm going to do a little thought experiment here. 326 00:15:32,000 --> 00:15:35,000 This is a Great White Shark that ate some of my traps. 327 00:15:35,000 --> 00:15:38,000 We pulled it up; up it comes. So, it's out there with me at night. 328 00:15:38,000 --> 00:15:41,000 So, I'm swimming along, and it takes off my leg. 329 00:15:41,000 --> 00:15:44,000 I'm 80 miles from shore, what's going to happen to me? 330 00:15:44,000 --> 00:15:46,000 Well now, I die. 331 00:15:46,000 --> 00:15:48,000 Five years from now, this is what I hope happens to me: 332 00:15:48,000 --> 00:15:51,000 I'm taken back to the boat, I'm given a gas mask: 333 00:15:51,000 --> 00:15:54,000 80 parts per million hydrogen sulfide. 334 00:15:54,000 --> 00:15:58,000 I'm then thrown in an ice pond, I'm cooled 15 degrees lower 335 00:15:58,000 --> 00:16:02,000 and I could be taken to a critical care hospital. 336 00:16:02,000 --> 00:16:04,000 And the reason I could do that is because we mammals 337 00:16:04,000 --> 00:16:07,000 have gone through a series of these hydrogen sulfide events, 338 00:16:07,000 --> 00:16:09,000 and our bodies have adapted. 339 00:16:09,000 --> 00:16:13,000 And we can now use this as what I think will be a major medical breakthrough. 340 00:16:13,000 --> 00:16:15,000 This is Mark Roth. He was funded by DARPA. 341 00:16:15,000 --> 00:16:19,000 Tried to figure out how to save Americans after battlefield injuries. 342 00:16:19,000 --> 00:16:21,000 He bleeds out pigs. 343 00:16:21,000 --> 00:16:24,000 He puts in 80 parts per million hydrogen sulfide -- 344 00:16:24,000 --> 00:16:27,000 the same stuff that survived these past mass extinctions -- 345 00:16:27,000 --> 00:16:29,000 and he turns a mammal into a reptile. 346 00:16:29,000 --> 00:16:33,000 "I believe we are seeing in this response the result of mammals and reptiles 347 00:16:33,000 --> 00:16:36,000 having undergone a series of exposures to H2S." 348 00:16:36,000 --> 00:16:38,000 I got this email from him two years ago; 349 00:16:38,000 --> 00:16:41,000 he said, "I think I've got an answer to some of your questions." 350 00:16:41,000 --> 00:16:43,000 So, he now has taken mice down 351 00:16:43,000 --> 00:16:47,000 for as many as four hours, sometimes six hours, 352 00:16:47,000 --> 00:16:49,000 and these are brand-new data he sent me on the way over here. 353 00:16:49,000 --> 00:16:54,000 On the top, now, that is a temperature record of a mouse who has gone through -- 354 00:16:54,000 --> 00:16:56,000 the dotted line, the temperatures. 355 00:16:56,000 --> 00:16:58,000 So, the temperature starts at 25 centigrade, 356 00:16:58,000 --> 00:16:59,000 and down it goes, down it goes. 357 00:16:59,000 --> 00:17:01,000 Six hours later, up goes the temperature. 358 00:17:01,000 --> 00:17:06,000 Now, the same mouse is given 80 parts per million hydrogen sulfide 359 00:17:06,000 --> 00:17:08,000 in this solid graph, 360 00:17:08,000 --> 00:17:10,000 and look what happens to its temperature. 361 00:17:10,000 --> 00:17:12,000 Its temperature drops. 362 00:17:12,000 --> 00:17:16,000 It goes down to 15 degrees centigrade from 35, 363 00:17:16,000 --> 00:17:19,000 and comes out of this perfectly fine. 364 00:17:19,000 --> 00:17:22,000 Here is a way we can get people to critical care. 365 00:17:22,000 --> 00:17:27,000 Here's how we can bring people cold enough to last till we get critical care. 366 00:17:28,000 --> 00:17:32,000 Now, you're all thinking, yeah, what about the brain tissue? 367 00:17:32,000 --> 00:17:35,000 And so this is one of the great challenges that is going to happen. 368 00:17:35,000 --> 00:17:37,000 You're in an accident. You've got two choices: 369 00:17:37,000 --> 00:17:40,000 you're going to die, or you're going to take the hydrogen sulfide 370 00:17:40,000 --> 00:17:43,000 and, say, 75 percent of you is saved, mentally. 371 00:17:43,000 --> 00:17:45,000 What are you going to do? 372 00:17:45,000 --> 00:17:48,000 Do we all have to have a little button saying, Let me die? 373 00:17:48,000 --> 00:17:50,000 This is coming towards us, 374 00:17:50,000 --> 00:17:52,000 and I think this is going to be a revolution. 375 00:17:52,000 --> 00:17:55,000 We're going to save lives, but there's going to be a cost to it. 376 00:17:55,000 --> 00:17:57,000 The new view of mass extinctions is, yes, we were hit, 377 00:17:57,000 --> 00:17:59,000 and, yes, we have to think about the long term, 378 00:17:59,000 --> 00:18:01,000 because we will get hit again. 379 00:18:01,000 --> 00:18:03,000 But there's a far worse danger confronting us. 380 00:18:03,000 --> 00:18:06,000 We can easily go back to the hydrogen sulfide world. 381 00:18:06,000 --> 00:18:08,000 Give us a few millennia -- 382 00:18:08,000 --> 00:18:10,000 and we humans should last those few millennia -- 383 00:18:10,000 --> 00:18:14,000 will it happen again? If we continue, it'll happen again. 384 00:18:14,000 --> 00:18:16,000 How many of us flew here? 385 00:18:16,000 --> 00:18:18,000 How many of us have gone through 386 00:18:18,000 --> 00:18:21,000 our entire Kyoto quota 387 00:18:21,000 --> 00:18:23,000 just for flying this year? 388 00:18:23,000 --> 00:18:26,000 How many of you have exceeded it? Yeah, I've certainly exceeded it. 389 00:18:26,000 --> 00:18:29,000 We have a huge problem facing us as a species. 390 00:18:29,000 --> 00:18:31,000 We have to beat this. 391 00:18:31,000 --> 00:18:35,000 I want to be able to go back to this reef. Thank you. 392 00:18:35,000 --> 00:18:41,000 (Applause) 393 00:18:41,000 --> 00:18:43,000 Chris Anderson: I've just got one question for you, Peter. 394 00:18:43,000 --> 00:18:45,000 Am I understanding you right, that what you're saying here 395 00:18:45,000 --> 00:18:47,000 is that we have in our own bodies 396 00:18:47,000 --> 00:18:51,000 a biochemical response to hydrogen sulfide 397 00:18:51,000 --> 00:18:54,000 that in your mind proves that there have been past mass extinctions 398 00:18:54,000 --> 00:18:56,000 due to climate change? 399 00:18:56,000 --> 00:18:58,000 Peter Ward: Yeah, every single cell in us 400 00:18:58,000 --> 00:19:01,000 can produce minute quantities of hydrogen sulfide in great crises. 401 00:19:02,000 --> 00:19:03,000 This is what Roth has found out. 402 00:19:03,000 --> 00:19:05,000 So, what we're looking at now: does it leave a signal? 403 00:19:05,000 --> 00:19:07,000 Does it leave a signal in bone or in plant? 404 00:19:07,000 --> 00:19:10,000 And we go back to the fossil record and we could try to detect 405 00:19:10,000 --> 00:19:12,000 how many of these have happened in the past. 406 00:19:12,000 --> 00:19:14,000 CA: It's simultaneously 407 00:19:14,000 --> 00:19:17,000 an incredible medical technique, but also a terrifying ... 408 00:19:17,000 --> 00:19:20,000 PW: Blessing and curse.