Jeg begynder med dette dejlige billede fra min barndom. Jeg elsker science fiction film. Her er den: "Denne Ø kaldet Jorden." og overlad blot Hollywood om at gøre det rigtigt. Fremstillingen tog to et halvt år. (latter) Altså - selv creationisterne giver os 6.000 år, men Hollywood vil ikke stå tilbage. I den film ser vi, hvor vi tror er derude: Flyvende tallerkner og rumvæsner. Enhver planet har et rumvæsen, og alle fjerne verdener har en flyvende tallerken og de bevæger sig med stor hastighed.
So, I want to start out with this beautiful picture from my childhood. I love the science fiction movies. Here it is: "This Island Earth." And leave it to Hollywood to get it just right. Two-and-a-half years in the making. (Laughter) I mean, even the creationists give us 6,000, but Hollywood goes to the chase. And in this movie, we see what we think is out there: flying saucers and aliens. Every world has an alien, and every alien world has a flying saucer, and they move about with great speed. Aliens.
Don Brownlee - min ven - og jeg blev til sidst trætte af at tænde for fjernsynet og se rumskibe og rumvæsner hver aften, og prøvede at skrive et mod-argument mod det, og vise, hvad der virkelig skal til, for en Jord kan være beboelig. For at en planet kan være Jorden, kan være et sted hvor man sandsynligvis vil have ikke blot liv, men kompleksitet som kræver en enorm evolution, og derfor konstante livsbetingelser. I år 2000 skrev vi bogen "En Sjælden Jord". Vi spurgte dengang: Tænk ikke på hvor Jorden befinder sig i rummet, men på hvor længe har Jorden været Jorden ? Hvis man går 2 milliarder år tilbage så er man ikke på en Jord-lignende planet. Dét vi kalder en Jord-lignende planet, findes faktisk kun i et meget kort tidsrum.
Well, Don Brownlee, my friend, and I finally got to the point where we got tired of turning on the TV and seeing the spaceships and seeing the aliens every night, and tried to write a counter-argument to it, and put out what does it really take for an Earth to be habitable, for a planet to be an Earth, to have a place where you could probably get not just life, but complexity, which requires a huge amount of evolution, and therefore constancy of conditions. So, in 2000 we wrote "Rare Earth." In 2003, we then asked, let's not think about where Earths are in space, but how long has Earth been Earth? If you go back two billion years, you're not on an Earth-like planet any more. What we call an Earth-like planet is actually a very short interval of time.
Bogen "En Sjælden Jord", lærte mig faktisk en masse om at møde offentligheden. Jeg fik straks en invitation fra en science fiction kongres. og med den største seriøsitet jeg gik jeg på scenen. David Brin skulle debattere med mig, og som jeg gik på scenen, begyndte en flok på hundrede at buh'e lystigt. Der var en pige, som kom op og sagde "Min far siger at du er djævlen selv". Man kan ikke tage folks rumvæsner fra dem og forvente at de forbliver ens venner. Vel, efter debatten hvor jeg talte med Paul Allen og gav ham min bog "En Sjælden Jord", og Jill Tarter var den, og hun vendte sig mod mig, og så på mig med et blik, akkurat som pigen i "Eksorcisten" "Det brænder ! Det brænder !" SETI vil ikke høre om det her. SETI vil have, at der er 'noget' derude. Jeg bifalder faktisk SETI, men vi har ikke hørt noget endnu. Jeg mener vi skal begynde at tænke på hvad der er en god planet og hvad der ikke er.
Well, "Rare Earth" actually taught me an awful lot about meeting the public. Right after, I got an invitation to go to a science fiction convention, and with all great earnestness walked in. David Brin was going to debate me on this, and as I walked in, the crowd of a hundred started booing lustily. I had a girl who came up who said, "My dad says you're the devil." You cannot take people's aliens away from them and expect to be anybody's friends. Well, the second part of that, soon after -- and I was talking to Paul Allen; I saw him in the audience, and I handed him a copy of "Rare Earth." And Jill Tarter was there, and she turned to me, and she looked at me just like that girl in "The Exorcist." It was, "It burns! It burns!" Because SETI doesn't want to hear this. SETI wants there to be stuff out there. I really applaud the SETI efforts, but we have not heard anything yet. And I really do think we have to start thinking about what's a good planet and what isn't.
Jeg viser dette billede, fordi det viser mig, at selvom SETI faktisk måtte høre noget, kan vi så regne ud hvad de sagde ? Fordi dette billede blev sendt mellem to store intelligenser på Jorden: en Mac og en PC. Og de kan ikke engang på bogstaverne på plads. (latter) Så hvordan skal vi kunne tale med rumvæsner ? Og hvis de er 50 lysår borte og vi kontakter dem og man blah blah blah blah og så kommer det tilbage 50 lysår senere med "Kan I gentage det ?" Så har vi håret i postkassen.
Now, I throw this slide up because it indicates to me that, even if SETI does hear something, can we figure out what they said? Because this was a slide that was passed between the two major intelligences on Earth -- a Mac to a PC -- and it can't even get the letters right -- (Laughter) -- so how are we going to talk to the aliens? And if they're 50 light years away, and we call them up, and you blah, blah, blah, blah, blah, and then 50 years later it comes back and they say, Please repeat? I mean, there we are.
Vores planet er en god planet, fordi den kan opbevare vand. Mars er en dårlig planet, men den er stadig god nok til at man kan rejse derhen og til at leve på dens overflade, hvis man er beskyttet. Men Venus er meget dårlig - den værste - planet. Selvom den er Jord-lignende, og selvom der i sin tidlige historie meget vel kan have Jord-lignende liv, så bukkede den under for en løbsk drivhus-virkning der er ca 400 °C på overfladen, p.gr.a. en voldsom kuldioxid.
Our planet is a good planet because it can keep water. Mars is a bad planet, but it's still good enough for us to go there and to live on its surface if we're protected. But Venus is a very bad -- the worst -- planet. Even though it's Earth-like, and even though early in its history it may very well have harbored Earth-like life, it soon succumbed to runaway greenhouse -- that's an 800 degrees [Fahrenheit] surface -- because of rampant carbon dioxide.
Vi ved fra astrobiologien, at vi nu forudsige, hvad der vil ske med vores planet. Vi er lige nu i de dejlige periode for livs-muligheder - i det mindste for planeten Jorden - som fulgte efter den første horrible mikrobiologiske tidsalder. I den Cambriske eksplosion, opstod livet fra sumpene kompleksitet opstod og så vidt vi ved, så er vi halvvejs igennem. Der kan eksistere dyr på denne planet i lige så lang tid, som de allerede har eksisteret, før vi kommer ind i den anden mikrobilogiske tidsalder. Og de vil ske, paradoksalt nok -- i betragtning af alt, hvad du hører om den globale opvarmning-- når vi når CO2 på 10 dele pr. million. Vi vil ikke længere have planter som kan have nogen fotosyntese, og så ryger dyrene ud. Efter det har vi sandsynligvis syv milliarder år. Solens intensitet stiger, og endelig, efter omkring 12 milliarder år siden sin begyndelse opsluges Jorden af en stor Sol, og dette er, hvad der er tilbage. Så en planet, som os, vil have en alder og en høj alder, og vi befinder os i sin gyldne sommer-alder lige nu.
Well, we know from astrobiology that we can really now predict what's going to happen to our particular planet. We are right now in the beautiful Oreo of existence -- of at least life on Planet Earth -- following the first horrible microbial age. In the Cambrian explosion, life emerged from the swamps, complexity arose, and from what we can tell, we're halfway through. We have as much time for animals to exist on this planet as they have been here now, till we hit the second microbial age. And that will happen, paradoxically -- everything you hear about global warming -- when we hit CO2 down to 10 parts per million, we are no longer going to have to have plants that are allowed to have any photosynthesis, and there go animals. So, after that we probably have seven billion years. The Sun increases in its intensity, in its brightness, and finally, at about 12 billion years after it first started, the Earth is consumed by a large Sun, and this is what's left. So, a planet like us is going to have an age and an old age, and we are in its golden summer age right now.
Men der er to skæbner til alt, er der ikke? En masse af jer vil dø af alderdom, men nogle af jer, kedeligt nok, vil dø i en ulykke. Og det er også en planets skæbne. Jorden, hvis vi er heldige nok --hvis den ikke bliver ramt af en Hale-Bopp, eller bliver sprængt af en supernova i nærheden i de næste syv milliarder år--. er under vore fødder. Men hvad med død ved et uheld ? Palæontologer har i de sidste 200 år kortlagt død. Mærkeligt nok så var udslettelse som begreb, slet ikke tænkt på indtil Baron Cuvier i Frankrig fandt denne første mastodon. Han kunne ikke matche det med nogen knogle på planeten, og han sagde: Aha! Den er uddød. Og meget snart derefter, begyndte fossilerne at give en meget klar idé om, hvor mange planter og dyr, der har været siden kompleks liv virkelig begyndte at efterlade et meget interessante fossile spor. I det komplekse spor af fossiler, der var tidspunkter, hvor masser af ting syntes at dø ud meget hurtigt, og far/mor geologerne kaldt disse "masseudslettelser."
But there's two fates to everything, isn't there? Now, a lot of you are going to die of old age, but some of you, horribly enough, are going to die in an accident. And that's the fate of a planet, too. Earth, if we're lucky enough -- if it doesn't get hit by a Hale-Bopp, or gets blasted by some supernova nearby in the next seven billion years -- we'll find under your feet. But what about accidental death? Well, paleontologists for the last 200 years have been charting death. It's strange -- extinction as a concept wasn't even thought about until Baron Cuvier in France found this first mastodon. He couldn't match it up to any bones on the planet, and he said, Aha! It's extinct. And very soon after, the fossil record started yielding a very good idea of how many plants and animals there have been since complex life really began to leave a very interesting fossil record. In that complex record of fossils, there were times when lots of stuff seemed to be dying out very quickly, and the father/mother geologists called these "mass extinctions."
Alt sammen mentes at være enten en handling af Gud eller måske lange, langsomme klimaændringer, og det ændredes for alvor i 1980, i dette klippefremspring i nærheden af Gubbio, hvor Walter Alvarez, forsøgte at finde ud af hvad tidsforskellen var mellem disse hvide klipper, som indeholdt skabninger fra kridttiden, og de lyserøde klipper ovenfor, som indeholdt tertiære fossiler. Hvor lang tid tog det for at gå fra det ene system til næste? Og hvad de fandt, var noget uventet. De fandt, i dette mellemrum, et meget tyndt lerlag, og dette lerlag--dette meget tyndt rødt lag her-- er fyldt med iridium. Og ikke bare iridium; Det er fyldt med glasagtig spherules, og det er fyldt med kvarts korn der har været udsat for et enormt pres: "chok kvarts".
All along it was thought to be either an act of God or perhaps long, slow climate change, and that really changed in 1980, in this rocky outcrop near Gubbio, where Walter Alvarez, trying to figure out what was the time difference between these white rocks, which held creatures of the Cretaceous period, and the pink rocks above, which held Tertiary fossils. How long did it take to go from one system to the next? And what they found was something unexpected. They found in this gap, in between, a very thin clay layer, and that clay layer -- this very thin red layer here -- is filled with iridium. And not just iridium; it's filled with glassy spherules, and it's filled with quartz grains that have been subjected to enormous pressure: shock quartz.
I denne dias er det hvide kridt, og denne kridt var deponeret i et varmt hav. Kalken selv er sammensat af plankton der er sunket ned fra havoverfladen til havbunden, således at 90 procent af sedimentet her er skelettet af levende ting, og så har man det millimeter-tykke røde lag, og så har du sort klippesten. Og den sorte klippesten er sedimentet på havbunden i fravær af plankton. Og det er, hvad der sker i en asteroid-katastrofe, fordi det er selvfølgelig, hvad det var. Dette er den berømte K-T. En 10-kilometer stort legeme ramte planeten. Virkningerne af det spredte dette meget tynde lag fra kollisionen, over hele planeten, og så fulgte meget hurtigt dinosaurernes uddøen, døden af disse smukke Ammoniter, Leconteiceras her og Celaeceras her, og så meget andet.
Now, in this slide the white is chalk, and this chalk was deposited in a warm ocean. The chalk itself's composed by plankton which has fallen down from the sea surface onto the sea floor, so that 90 percent of the sediment here is skeleton of living stuff, and then you have that millimeter-thick red layer, and then you have black rock. And the black rock is the sediment on the sea bottom in the absence of plankton. And that's what happens in an asteroid catastrophe, because that's what this was, of course. This is the famous K-T. A 10-kilometer body hit the planet. The effects of it spread this very thin impact layer all over the planet, and we had very quickly the death of the dinosaurs, the death of these beautiful ammonites, Leconteiceras here, and Celaeceras over here, and so much else.
Jeg mener, det må være sandt, fordi vi har haft to Hollywood blockbustere siden dengang, og dette paradigme, fra 1980 til omkring 2000, ændrede totalt, hvordan vi geologer tænkte i katastrofer. Forud for det, var enheds-princippet det dominerende paradigme: det faktum, at hvis der skete noget på planeten i fortiden, så er der processer i nutiden, der vil forklare det. Men vi har ikke oplevet en stor asteroide-kollision, så dette er en slags "neo-katastrophism", og det tog omkring 20 år for den videnskabelige establishment at fatte: Ja, vi blev ramt; og ja, virkningerne af dette hit forårsagede en større masseudslettelse.
I mean, it must be true, because we've had two Hollywood blockbusters since that time, and this paradigm, from 1980 to about 2000, totally changed how we geologists thought about catastrophes. Prior to that, uniformitarianism was the dominant paradigm: the fact that if anything happens on the planet in the past, there are present-day processes that will explain it. But we haven't witnessed a big asteroid impact, so this is a type of neo-catastrophism, and it took about 20 years for the scientific establishment to finally come to grips: yes, we were hit; and yes, the effects of that hit caused a major mass extinction.
Der findes fem større masseudslettelser i de sidste 500 millioner år, kaldet De Store Fem. De spænder fra 450 millioner år siden til den sidste, K-T, nummer fire, men den største af alle var P eller Perm-udslettelsen, undertiden kaldet moderen til alle masseudslettelser. Og hver eneste af disse er efterfølgende begrundet med en kollision med et stort himmellegeme. Men er det sandt?
Well, there are five major mass extinctions over the last 500 million years, called the Big Five. They range from 450 million years ago to the last, the K-T, number four, but the biggest of all was the P, or the Permian extinction, sometimes called the mother of all mass extinctions. And every one of these has been subsequently blamed on large-body impact. But is this true?
Den seneste, Perm, blev anset for at have været en kollision på grund af denne smukke struktur til højre. Dette er en Buckminster-fulleren, en carbon-60. Fordi det ligner disse frygtelige geodætiske kupler fra mit elskede 60'erne, kaldes de "buckyballs." (fodbolds-molekyle) Dette bevis blev brugt til at foreslå at en komet ramt os i slutningen af Perm for 250 millioner år siden, Og når kometen rammer, frembringer trykket buckyballs, og det indfanger dele af kometen. Helium-3: meget sjælden på overfladen af jorden, meget almindelig i rummet.
The most recent, the Permian, was thought to have been an impact because of this beautiful structure on the right. This is a Buckminsterfullerene, a carbon-60. Because it looks like those terrible geodesic domes of my late beloved '60s, they're called "buckyballs." This evidence was used to suggest that at the end of the Permian, 250 million years ago, a comet hit us. And when the comet hits, the pressure produces the buckyballs, and it captures bits of the comet. Helium-3: very rare on the surface of the Earth, very common in space.
Men er sandt? I 1990, mens jeg arbejdede på K-T udslettelsen i 10 år, rejste jeg til Sydafrika for at arbejde to gange om året i den store Karoo ørken. Jeg var så heldig at se ændringen af det Sydafrika til det nye Sydafrika, som årene gik. Jeg arbejdede på Perm udslettelsen, og camperede ved denne Boer kirkegård i flere måneder ad gangen. Fossiler er noget ekstraordinært. Man stirrer på sine meget fjerne forfædre. Disse er pattedyrs-lignende krybdyr. De er kulturelt usynlige. Vi laver ikke film om disse. Dette er en Gorgonopsian eller en Gorgon. Det er en 46-cm langt kranium af et dyr der sandsynligvis var syv eller otte meter lang, udstrakt som en øgle, og sandsynligvis havde den et hoved som en løve. Dette er den øverste kødæder, T-Rex af sin tid. Men her er der masser af ting. Dette er min stakkels søn, Patrick. (Latter) Dette kaldes paleontological børnemishandling. Stå stille, du er skalaen. (Latter)
But is this true? In 1990, working on the K-T extinction for 10 years, I moved to South Africa to begin work twice a year in the great Karoo desert. I was so lucky to watch the change of that South Africa into the new South Africa as I went year by year. And I worked on this Permian extinction, camping by this Boer graveyard for months at a time. And the fossils are extraordinary. You know, you're gazing upon your very distant ancestors. These are mammal-like reptiles. They are culturally invisible. We do not make movies about these. This is a Gorgonopsian, or a Gorgon. That's an 18-inch long skull of an animal that was probably seven or eight feet, sprawled like a lizard, probably had a head like a lion. This is the top carnivore, the T-Rex of its time. But there's lots of stuff. This is my poor son, Patrick. (Laughter) This is called paleontological child abuse. Hold still, you're the scale. (Laughter)
Der var store ting dengang. 55 arter af pattedyrs-lignende krybdyr. Pattedyrenes tidsalder var godt og grundigt begyndt 250 millioner år siden... ... og så skete der en katastrofe. Dernæst kom dinosaurernes tidsalder. Det var en fejltagelse. Det burde aldrig være sket. Men det gjorde det. Nu, heldigvis, denne Thrinaxodon, med størrelse af en rødkælk, her: Dette er et kranium, som jeg havde opdaget, lige før jeg tog dette billede-- der er en kuglepen som skala; Det er virkeligt lille-- Dette er i nedre Trias, efter at masseudslettelsen var slut. Man kan se øjenhulen og man kan se de små tænder foran. Hvis den ikke overlever, så er jeg ikke den ting, som giver dette foredrag. Noget andet må være det, fordi hvis den ikke overlever, så er vi ikke her; der vil ingen pattedyr være. Det er meget tæt på; én art lirkes gennem.
There was big stuff back then. Fifty-five species of mammal-like reptiles. The age of mammals had well and truly started 250 million years ago ... ... and then a catastrophe happened. And what happens next is the age of dinosaurs. It was all a mistake; it should have never happened. But it did. Now, luckily, this Thrinaxodon, the size of a robin egg here: this is a skull I've discovered just before taking this picture -- there's a pen for scale; it's really tiny -- this is in the Lower Triassic, after the mass extinction has finished. You can see the eye socket and you can see the little teeth in the front. If that does not survive, I'm not the thing giving this talk. Something else is, because if that doesn't survive, we are not here; there are no mammals. It's that close; one species ekes through.
Kan vi sige noget om mønstret af hvem der overlever, og hvem der ikke gør? Her er en slags slutning af de 10 års arbejde. Områderne for tingene -- den røde linje er masseudslettelsen. Men vi fik overlevere, og ting der kommer igennem, og det viser sig at de ting, der kom igennem, var fortrinsvis koldblodede. Varmblodede dyr bliver et kæmpe hit på dette tidspunkt. De overlevende, der kom igennem, frembragte denne verden af krokodille-lignende skabninger. Der er ingen dinosaurere endnu; blot denne langsomme, krybdyrsagtige, skællet, grimme, sumpede sted, med et par små pattedyrsom i udkanten. Og der de ville skjule sig i 160 millioner år, indtil de befries af at K-T asteroide.
Well, can we say anything about the pattern of who survives and who doesn't? Here's sort of the end of that 10 years of work. The ranges of stuff -- the red line is the mass extinction. But we've got survivors and things that get through, and it turns out the things that get through preferentially are cold bloods. Warm-blooded animals take a huge hit at this time. The survivors that do get through produce this world of crocodile-like creatures. There's no dinosaurs yet; just this slow, saurian, scaly, nasty, swampy place with a couple of tiny mammals hiding in the fringes. And there they would hide for 160 million years, until liberated by that K-T asteroid.
Så hvis der ikke var nogen kollision, hvad var det så ? Jeg tror, at vi vendte tilbage, gang på gang, til den Pre-Cambrianske verden, den første mikrobielle tidsalder, og mikroberne er stadig derude. De hader os dyr. De ønsker virkelig deres verden tilbage. Og de har forsøgt igen og igen og igen. Det får mig til at tro, at livet forårsager disse masseudslettelser fordi det er i sagens natur anti-Gaia. Hele denne Gaia idé, at liv gør verden bedre for sig selv -- har nogen på en motorvej på en fredag eftermiddag i Los Angeles troet på Gaia teorien? Nej.
So, if not impact, what? And the what, I think, is that we returned, over and over again, to the Pre-Cambrian world, that first microbial age, and the microbes are still out there. They hate we animals. They really want their world back. And they've tried over and over and over again. This suggests to me that life causing these mass extinctions because it did is inherently anti-Gaian. This whole Gaia idea, that life makes the world better for itself -- anybody been on a freeway on a Friday afternoon in Los Angeles believing in the Gaia theory? No.
Så, jeg tror virkelig, at der er et alternativ, og at livet faktisk forsøgte, at gøre det af med sig selv -- ikke bevidst, men bare fordi det gør det. Og her er våbnet, som det lader til, at det brugte det i de sidste 500 millioner år. Der er mikrober, som gennem deres stofskifte, producerer svovlbrinte, og de gør det i store mængder. Svovlbrinte er meget giftigt for os mennesker. Så lidt som 200 dele pr. million vil dræbe én. Man behøver kun at gå til det sorte hav eller et par andre steder--nogle søer-- og dykke ned, og man vil opdage, at vandet, i sig selv, bliver lilla. Det bliver lilla fra tilstedeværelsen af talrige mikrober som skal have sollys og skal have hydrogensulfid, og vi kan spore deres tilstedeværelse i dag - vi kan se dem-- men vi kan også spore deres tilstedeværelse i fortiden.
So, I really suspect there's an alternative, and that life does actually try to do itself in -- not consciously, but just because it does. And here's the weapon, it seems, that it did so over the last 500 million years. There are microbes which, through their metabolism, produce hydrogen sulfide, and they do so in large amounts. Hydrogen sulfide is very fatal to we humans. As small as 200 parts per million will kill you. You only have to go to the Black Sea and a few other places -- some lakes -- and get down, and you'll find that the water itself turns purple. It turns purple from the presence of numerous microbes which have to have sunlight and have to have hydrogen sulfide, and we can detect their presence today -- we can see them -- but we can also detect their presence in the past.
Og de sidste tre år har det været et enormt gennembrud i et helt nyt felt. Jeg er næsten uddød-- Jeg er en palæontolog, der indsamler fossiler. Men den nye bølge af palæontologer -min graduate studerende- indsamler biomarkører. De tager selve sedimentetet, de udvinder olien fra det, og ud fra det, kan de frembringe forbindelser der viser sig for at være meget specifikke for bestemte mikrobielle grupper. Fordi lipider er så hårdt, kan de forblive konserveret i sedimenterne og holde i hundreder af millioner af år, og udvindes og fortælle os, hvem der var der.
And the last three years have seen an enormous breakthrough in a brand-new field. I am almost extinct -- I'm a paleontologist who collects fossils. But the new wave of paleontologists -- my graduate students -- collect biomarkers. They take the sediment itself, they extract the oil from it, and from that they can produce compounds which turn out to be very specific to particular microbial groups. It's because lipids are so tough, they can get preserved in sediment and last the hundreds of millions of years necessary, and be extracted and tell us who was there.
Og vi ved, hvem der var der. I slutningen af Perm, på mange af disse masseudslettelses-grænser, Dette er, hvad vi ser: isorenieratene. Det er meget specifikt. Det kan kun ske, hvis havets overflade ingen ilt har, og er helt mættet med svovlbrinte-- nok, for eksempel, til at komme ud af opløsningen. Dette førte Lee Kump, og andre fra Penn State og min gruppe, til at foreslå, hvad jeg kalder Kump hypotese: mange af de massive udslettelser, blev forårsaget af et sænket ilt-niveau, af et høj CO2-niveau. Og den værste virkning af global opvarmning, viste sig at være den hydrogensulfid, som produceres i havene.
And we know who was there. At the end of the Permian, at many of these mass extinction boundaries, this is what we find: isorenieratene. It's very specific. It can only occur if the surface of the ocean has no oxygen, and is totally saturated with hydrogen sulfide -- enough, for instance, to come out of solution. This led Lee Kump, and others from Penn State and my group, to propose what I call the Kump Hypothesis: many of the mass extinctions were caused by lowering oxygen, by high CO2. And the worst effect of global warming, it turns out: hydrogen sulfide being produced out of the oceans.
Hvad er kilden hertil? I dette tilfælde, har kilden igen og igen været en oversvømmelse af lava. Dette er en visning af jorden nu, hvis vi fjerner en masse. Og hver af disse ligner en brintbombe; faktisk er virkningerne er endnu værre. Det er når dybtliggende materiale, kommer op til overfladen, breder sig over overfladen af planeten. Det er ikke den lava, som dræber noget, Det er den kuldioxid, der kommer med den. Dette er ikke Volvo'er; Dette er vulkaner. Men kuldioxid er kuldioxid.
Well, what's the source of this? In this particular case, the source over and over has been flood basalts. This is a view of the Earth now, if we extract a lot of it. And each of these looks like a hydrogen bomb; actually, the effects are even worse. This is when deep-Earth material comes to the surface, spreads out over the surface of the planet. Well, it's not the lava that kills anything, it's the carbon dioxide that comes out with it. This isn't Volvos; this is volcanoes. But carbon dioxide is carbon dioxide.
Dette er nye data som Rob Berner og jeg -- fra Yale -- har sat sammen, og hvad vi forsøger at gøre nu er at spore mængden af kuldioxid i klippelagene. og vi kan gøre dette med en bred vifte af metoder, og sætte alle de røde linjer her, da disse --hvad jeg kalder drivhus-masseudslettelse--fandt sted. Og to ting, som virkelig er klart for mig, er, at disse udslettelser finder sted, når CO2 går op. Men den anden ting, der ikke er vist her: Jorden har aldrig haft nogen is på det når vi har haft 1.000 parts per million CO2. Vi er på 380 og stigende. Vi burde nå de tusinde i løbet af tre århundreder, men min ven David Battisti i Seattle mener 100 år. Så der forsvinder iskapperne, og her kommer 80 meters havstigning. Jeg bor i et hus med udsigt; Jeg vil få mig en strandgrund.
So, these are new data Rob Berner and I -- from Yale -- put together, and what we try to do now is track the amount of carbon dioxide in the entire rock record -- and we can do this from a variety of means -- and put all the red lines here, when these -- what I call greenhouse mass extinctions -- took place. And there's two things that are really evident here to me, is that these extinctions take place when CO2 is going up. But the second thing that's not shown on here: the Earth has never had any ice on it when we've had 1,000 parts per million CO2. We are at 380 and climbing. We should be up to a thousand in three centuries at the most, but my friend David Battisti in Seattle says he thinks a 100 years. So, there goes the ice caps, and there comes 240 feet of sea level rise. I live in a view house now; I'm going to have waterfront.
Okay, hvad er konsekvensen? Havene bliver sandsynligvis lilla. Og vi mener, dette er grunden til, at komplekst liv tog så lang tid, for at finde sted på planeten jorden. Vi havde disse hydrogensulfid-oceaner over en meget lang periode. De hindrer komplekst liv i at eksistere. Vi ved, at hydrogensulfid lige nu bryder ud et par steder på planeten. Jeg viser dette dias -- det er faktisk mig for to måneder siden-- Jeg viser dette dias i fordi her er mit favorit-dyr, chambered nautilus. Den var på denne planet, da dyrene først begyndte--500 millioner år. Dette er et sporings-eksperiment. Hvis nogen af jer dykkere, ønsker at blive involveret i et af de fedeste projekter nogensinde, Det ligger ved Great Barrier Reef. Og mens vi taler nu, sporer vi disse nautilus'ers adfærd.
All right, what's the consequence? The oceans probably turn purple. And we think this is the reason that complexity took so long to take place on planet Earth. We had these hydrogen sulfide oceans for a very great long period. They stop complex life from existing. We know hydrogen sulfide is erupting presently a few places on the planet. And I throw this slide in -- this is me, actually, two months ago -- and I throw this slide in because here is my favorite animal, chambered nautilus. It's been on this planet since the animals first started -- 500 million years. This is a tracking experiment, and any of you scuba divers, if you want to get involved in one of the coolest projects ever, this is off the Great Barrier Reef. And as we speak now, these nautilus are tracking out their behaviors to us.
Men det hænder at vi dykkere løber ind i problemer, så jeg har tænkt mig at lave et lille tankeeksperiment her. Dette er en stor hvid haj, der åd nogle af mine fælder. Vi trak den op. Her er den. Så det er mig derude om natten. Så - jeg svømmer, og det tager mit ben. Jeg er 80 km fra kysten. Hvad vil der ske med mig? I dag ville jeg dø. Fem år frem i tid, og dette er, hvad jeg håber vil ske for mig: Jeg bliver taget tilbage til båden, jeg får en gas-maske: 80 dele pr. million hydrogensulfid. Jeg bliver så lagt i et is-bad. Jeg bliver kølet 15 grader ned og kunne blive taget til intensiv behandling. Og grunden til at jeg kan gøre det er, fordi vi pattedyr har været igennem en række af disse hydrogensulfid-begivenheder og vores krop har tilpasset sig. Vi kan nu bruge dette til, hvad jeg tror vil blive et større medicinsk gennembrud.
But the thing about this is that every once in a while we divers can run into trouble, so I'm going to do a little thought experiment here. This is a Great White Shark that ate some of my traps. We pulled it up; up it comes. So, it's out there with me at night. So, I'm swimming along, and it takes off my leg. I'm 80 miles from shore, what's going to happen to me? Well now, I die. Five years from now, this is what I hope happens to me: I'm taken back to the boat, I'm given a gas mask: 80 parts per million hydrogen sulfide. I'm then thrown in an ice pond, I'm cooled 15 degrees lower and I could be taken to a critical care hospital. And the reason I could do that is because we mammals have gone through a series of these hydrogen sulfide events, and our bodies have adapted. And we can now use this as what I think will be a major medical breakthrough.
Dette er Mark Roth. Han blev finansieret af DARPA. Han forsøger at finde ud af hvordan man kan redde amerikanere efter skader på slagmarken. Han tapper svin for blod. Han tilfører 80 vægtdele pr. million hydrogensulfid-- det samme, som overlevede de seneste masseudslettelser-- og han forvandler et pattedyr til et krybdyr. "Jeg tror, vi i denne reaktion, ser resultatet af pattedyr og reptiler efter at have gennemgået en række eksponeringer af H2S." Jeg fik denne mail fra ham for to år siden: Han sagde, "Jeg tror, jeg har fundet et svar på nogle af dine spørgsmål." Han har nu han kølet en mus i så meget som fire timer, sommetider seks timer, og disse er splitter-nye data som han sendte mig på vej herover. På toppen, er der en temperatur-optegnelse for en mus, der har været igennem-- den stiplede linje, temperaturerne. Temperaturen starter ved 25 Celsius, og det går ned , det går ned. Seks timer senere, går det op i temperatur. OK - den samme mus gives 80 dele pr. million svovlbrinte i denne solide kurve, og se hvad der sker med temperaturen. Dens temperatur falder. Den går ned til 15 grader Celsius fra 35, og kommer helt fint ud af det.
This is Mark Roth. He was funded by DARPA. Tried to figure out how to save Americans after battlefield injuries. He bleeds out pigs. He puts in 80 parts per million hydrogen sulfide -- the same stuff that survived these past mass extinctions -- and he turns a mammal into a reptile. "I believe we are seeing in this response the result of mammals and reptiles having undergone a series of exposures to H2S." I got this email from him two years ago; he said, "I think I've got an answer to some of your questions." So, he now has taken mice down for as many as four hours, sometimes six hours, and these are brand-new data he sent me on the way over here. On the top, now, that is a temperature record of a mouse who has gone through -- the dotted line, the temperatures. So, the temperature starts at 25 centigrade, and down it goes, down it goes. Six hours later, up goes the temperature. Now, the same mouse is given 80 parts per million hydrogen sulfide in this solid graph, and look what happens to its temperature. Its temperature drops. It goes down to 15 degrees centigrade from 35, and comes out of this perfectly fine.
Her er en måde vi kan få folk til intensivbehandling. Sådan kan man gøre mennesker kolde længe nok indtil de kan få intensivbehandling. Nu, tænker i alle: Ja, men hvad med hjernevævet? Det er en af de store udfordringer, der kommer til at ske. Du er i en ulykke. Har du to valgmuligheder: Du vil dø, eller du vil tage svovlbrinte og, lad os sige, at 75 procent af dit mentale jeg vil bevares. Hvad vil du gøre? Har vi alle har en lille knap der siger, lad mig dø? Det er på vej, og jeg tror, at det vil blive en revolution. Vi kommer til at redde liv, men der vil være en omkostning ved det.
Here is a way we can get people to critical care. Here's how we can bring people cold enough to last till we get critical care. Now, you're all thinking, yeah, what about the brain tissue? And so this is one of the great challenges that is going to happen. You're in an accident. You've got two choices: you're going to die, or you're going to take the hydrogen sulfide and, say, 75 percent of you is saved, mentally. What are you going to do? Do we all have to have a little button saying, Let me die? This is coming towards us, and I think this is going to be a revolution. We're going to save lives, but there's going to be a cost to it.
Det nye syn på masseudslettelser er: Ja, vi blev ramt, og ja, vi skal tænke langsigtet, fordi vi vil blive ramt igen. Men der er en langt større fare, som konfronterer os. Vi kan nemt komme tilbage til hydrogensulfid-verdenen. Om et par årtusinder-- og menneskeheden burde vare de par årtusinder-- Vil det ske igen? Hvis vi fortsætter, vil det ske igen. Hvor mange af os fløj hertil? Hvor mange af os har opbrugt hele vores Kyoto kvote bare ved at flyve i år? Hvor mange af jer har overskredet det? Ja, jeg har helt sikkert overskredet det. Vi har et kæmpe problem, som vi står over for som en art. Vi er nødt til at vinde over dette. Jeg vil gerne tilbage til dette rev. Tak.
The new view of mass extinctions is, yes, we were hit, and, yes, we have to think about the long term, because we will get hit again. But there's a far worse danger confronting us. We can easily go back to the hydrogen sulfide world. Give us a few millennia -- and we humans should last those few millennia -- will it happen again? If we continue, it'll happen again. How many of us flew here? How many of us have gone through our entire Kyoto quota just for flying this year? How many of you have exceeded it? Yeah, I've certainly exceeded it. We have a huge problem facing us as a species. We have to beat this. I want to be able to go back to this reef. Thank you.
(Bifald)
(Applause)
Chris Anderson: Jeg har lige fået et spørgsmål til dig, Peter. Jeg forstår dig ret, at hvad du siger her Vi har i vores egne kroppe en biokemisk reaktion på svovlbrinte der efter din mening beviser, at der har været masseudslettelser i fortiden, på grund af klimaændringer?
Chris Anderson: I've just got one question for you, Peter. Am I understanding you right, that what you're saying here is that we have in our own bodies a biochemical response to hydrogen sulfide that in your mind proves that there have been past mass extinctions due to climate change?
Peter Ward: Ja, hver enkelt celle i os kan producere små mængder hydrogensulfid i store kriser. Dette er, hvad Roth har fundet ud af. Så, hvad vi ser på nu: Efterlader det et signal? Efterlader det et signal i knogler eller planter? Og går vi tilbage til fossil-optegnelserne og kan vi prøve at fastslå, hvor mange af disse, der er sket i fortiden.
Peter Ward: Yeah, every single cell in us can produce minute quantities of hydrogen sulfide in great crises. This is what Roth has found out. So, what we're looking at now: does it leave a signal? Does it leave a signal in bone or in plant? And we go back to the fossil record and we could try to detect how many of these have happened in the past.
CA: Er det samtidig en utrolig medicinsk teknik, men også en skræmmende...
CA: It's simultaneously an incredible medical technique, but also a terrifying ...
PW: Velsignelse og forbandelse.
PW: Blessing and curse.