Hawaiian islands used to have several species of crows an they probably die diverge from those in the u. S. At least 700,000 years ago. So this is in a lot of ways a lot like the story of darwins finches where an animal arrived on, obviously, were not sure how exactly. But in very small numbers, and then species in different niches and able to survive in different habitat. But the difference is that in the case of the hawaiian crows most of the species died out after the first humans arrived, so whereas galapagos not inhabited till europeans arrived in hawaii, sea fairers arrived 1500 years ago. And already they brought with them a species like rats like the pacific rat that either outcompeted or potentially just ate up the young and the eggs of these crows so most of the species were already gone by the time europeans arrived. This is the last species that survived in to modern times. And it is native to the big island, island of hawaii and its been under terrible pressure both from habitat destruction, the hawaiian forest and introduced species. And by the 1980s, the population of alala so low that the state of hawaii began to take birds into captivity to try to save the species. And had turns out to have been actually quite fortunate because the last wild alaala seen in 2002. And the bird is now classified as extinct in the wild so this particular that youre looking at is named kanowi. He was born at the breeding facility which is on the island of maui and hes quite an odd duck as the saying goes. He was raised by people. And he doesnt seem to really selfidentify as a bird. [laughter] or o at least not as a crow not as a crow, one of the women who cares for him told me that he once fell in love with a spoon bill. So because of his, you know, lack of identification with other crows he refused to mate with the birds at the breeding facility so there are now about 100alala maybe more at the facility and roughly 50 females he had to choose from but refused to mate with any of them. And he is pretty old now in his 20s which is pretty old for a bird. And so for precisely that reason his genes are very important so couple of year ago he was transferred to the san diego zoo, where he came under the care of a reproductive physiologist named barbra durant and durant is hoping that he is going to provide some of his gametes so that she could rush over to maui and use them to art if i recallly inseminate one of the crows over there. Every spring when it is mating season, a durant you know who is a serious scientist, ph. D. Takes this bird on her lap. [laughter] yeah. And strokes him in a way that hes supposed to find extremely exciting. [laughter] an about a year ago i was out in san diego and he had at that point not yet delivered on this. But durant offered to introduce me to him. And he turns out to be a very charismatic sexually confused bird. [laughter] so he has this very spectacular cage, sort of almost like a suite how is that . And we could stand in it and he hopped over to us and it seemed to me that he definitely recognized durant and seemed embarrassed to see her. [laughter] yeah, that may be projection, of course, but he seems to maybe be embarrassed and durant had brought him some snacks. These little mice, hairless newborn mice which are known as pinkies theyre pink. So he hopped over to peck at them and crows are very smart birds as im sure you know, and they can imitate human speech and kanowi has a line he says i know. And it sounds a little bit demented, to me when he says that he sums up this very strange and sad situation we find ourselves in. Here we have this crow one of the very last survivors of his species, and people are going to incredible lengths to try to save up the species. Set up this breeding facility. Giving what amounts to hand jobs to crows. [laughter] and people really do care about animals. About what racials call the problem of sharing our earth with other creatures but at the same time were in a process of causing what has been called extinction with more and more species to the brink and more and more species over the brink. So kanowi situation brings together a lot of strands, his knowingness or knowing, i know seemed reflection almost on his own tragic situation. And i ended up ending the book with his story and he sort of is an emblem for what im going to talk to you about tonight. So what is the sixth extinction . Implication is there have been five earlier extengeses and that is exactly the case. So what youre looking at here in this graph is an analysis of the marines fossil records and theres a little bit of a complicated graph but baisktsly on the bottom of your left it is time before the present measured in millions of years. So 600 million years up to 0 up to the present. And where you see the big dips those are points when the number of marine families were looking at the marine record here only. Suddenly dropped. And if you remember from introductory bio a family is group above a genus so goes from there to attempt, and even one species from a family survived that family counts as a survivor. So at the species level, the losses at these points were much greater than is reflected in this graph. So these five major extinctions i should add many minor mass extinctions but these five major are referred to as the big five. And theyre simply moments when geologically speaking moments short amounts of time when the diversity of life on the planet for some reason plummeted. Two british paleontologists written a lot of on the subject anthony and paul wignal have described it as theres a significant proportion of the worlds biota in a geologically and significant amount of time. Another british paleontologist Michael Benton has used med tore of the tree of life during a mass extinction hes written vast flaws cut short as if attacked by crazed ax wielding madmen so the first of the extinctions took place at the end of what is known as the period that is 440 million years ago, and at that point, most of life was still confined to the ocean. So very little living on land. That was devastating event for marine life, but not for terrestrial life and there wasnt any fifth was 66 million years ago that was by far the most famous. S that the event that killed off the dinosaurs not just the dinosaurs but a lot of other groups most mammals an most reptiles, snakes for example, and also a lot of groups like tar areasaurs but i have a wondl illustration that i like. [laughter] and theres a pretty broad consensus that this was caused by asteroid impact so those guys are reacting to the asteroid impact. [laughter] so to say that were in a 6th extinction is pretty serious. And the reason that were in the sixth and some scientists will say were only on the verge of the sixth maybe we can prevent it still, and others would say were pretty deep into it already, is that were changing the world very, very radically, and very, very fast. Not unlike an asteroid. And, in fact, you will hear and i have heard a scientist say this time we human being are the asteroid. How are we doing this and changing the world on an asteroid like scale . Theres a lot of ways. But im going to just focus on three tonight. That is how were changing the atmosphere. How were changing oceans and how were with changing what darwin called principles of geographical distribution. So lets start with the atmosphere. Every year we humans are adding on order of ten billion metric ton was Carbon Dioxide from burnings fossil fuels you know this im not going to delabor it we drive our cars. We turn on our lights there are 7. 2 billion people on the planet right now. An it adds up. And what were doing when we burns to fossil fuels is were taking carbon that was buried urnt the earth over the course of hundreds of millions of years transferring it back up into the atmosphere. So were basically running geological history backwards at a very high speed were taking a process what took hundreds of millions of years to run and in one direction an running in the other direction many a matter of centuries an if you were an alien and you came to visit the earth you could conclude that what were doing that the fundamental purpose of society is to dissect this transfer as quick as poll to see how much we can get out of the ground and put up in the air and how fast we can do it. And if the aliens werent measuring this process they would say we were doing quite a good job. Were increasing co2 levels and hiewks were doing this once again were doing this once again from hawaii. From a place called observatory that is altitude of 11,000 feet on this huge volcanic mountain. Im sure most of you have seen this as the curve showing you atmosphere Carbon Dioxide levels measured continuously for over 50 years now. And what youre seeing on the y axis there is c02 levels an parts per million an there is time on the bottom there. And that tooth pattern is a seasonal component right, so in the winter when the trees of the Northern Hemisphere dropped their leaves, c02 levels go up, and when the summer when they put out their leaves and photosynthesis theres more plants and Northern Hemisphere summer, we get lower Carbon Dioxide levels. They take c02 out of the air and global co2 levels fall. And you may have read recently that c02 levels reach a new milestone 400 parts per million and that is true. Hay did. At the end of last winter briefly but they sense dropped again over the summer. Theyre now in that rising part of the curve that is a very recent measurement 296 parts per million an this saw tooth will continue in a couple of years from now and never go mete 400 parts per million and keep rising as long as we continue to put c02 into the atmosphere an we show no signs of this point of slowing down. And if we want to see how well were doing on this process, on a longer time scale, weve got to go back to ice core records. So what youre looking at here is a record of c02 from a famous ice core that was thrilled on antarctica. The whole ice sheet is layers and layers of snow, that were laid down year by year year bier and never melted. And as you can see here, youre looking at your left once again were going time is Going Forward from left to right. That is 800,000 years ago. In the left hand corner so that ice core goes back 800,000 years. And in these ice cores actually little bubbles of past atmospheres that scientists have figured out how to extraght and analyze and up and down patterns seeing c02 levels on the up and down axis there is up and down saw tooth things those are ice ages when c02 levels are low ice creeps down. All the way, you know, down here, and into places Like Washington state, and then creeps back up again. And there you see when people arrive the arrival around 200,000 years ago. So this is 8 glacial cycles and you can see that during that whole time during all of the 800 level the co2 levels never above 300 parts per million until recently and now rising what amounts it a vertical line straight up. And if you want to go even further back, you know then the ice runs out. But there are other ways of teasing out ancient atmospheres from the evidence that we have for example, from the shelf marine creatures that drop to the bottom of the sea and preserved for many millions of years and these methods are not as exact but they give us a pretty good picture of the past atmosphere. And it turns out if we want to find c02 levels that are higher than todays weve got to go back quite a long way. Probably around 20 million years ago to a period called the mia scene. Keep pouring co2 into the atmosphere the way we are we could reach levels you know by around the middle of this century. And if we keep on after that, we could reach levels not seen since around 50 million years ago probably by around the end of this century. And what is significant about this as all of you know is that c02 has Certain Properties that make a green house gas. Im not going to, you know, give you the Global Warming speel because you know it once again. This is very, very basic geophysics this Carbon Dioxide that it traps heat during the surface of the earth has been understood since 1850s so this wonderful contraption constructed back in the 1850s but a scientist named john kendall and he defined this machine because he was interested in looking at the property was different gases. And when he tested Carbon Dioxide he realized right away he found out something very, very important. Carbon dioxide is transparent in a visible part of the spectrum so lets light through and doesnt block light that comes in but partly opaque in the infrared part of the spectrum. Heat escaping from the earth and radiate back to space some of that gets blocked. And kendall once again in 1850s realized that was extremely important and that it kept the earth warmer than it would be if we had an atmosphere with no greens house gases. So that affect is often called the Natural Green house effect and it is critical it life as we know it, if we have no Green House Gases in our atmosphere our planet would be frozen and average temperature of about 0 degrees. So this has been understood for century and a half now, no news here. And if you know that c02 is heat trapping gas and you know were rapidly raising c02 levels all things equal you would expect average goal temperatures to be going up. Right . And, of course, that is whats happening. So this next light im going to show you is not a slide but it is a video made by nasa. And all you need to know to understand it is that as a color gets warmer you know what we consider warmer yellow and blue more cold, temperatures are colder. So this is a reconstruction of Global Temperatures going back to the 1880s done by nasa. Yeah, that is pretty dramatic so what does all of this mean for, you know, living things . Well, the icon of what it means to be, you know, an animal in a warming world has become the polar bear. Because polar bears, you know, hunt off sea ice which is very rapidly disappearing. But one of the points that i make in the book and it is now really not my point but a point made by the scientists that i went out with. Is that Climate Changes are likely to be even more devastating in the tropics. And there are couple of reasons for this. One of which is simply that the tropics are where most species live. So if you consider for a moment for example, trees. So canadas forest is largest intact forest left on the planet it covers almost a billion acres, and in that whole expanse theres only about 20 species of tree that you can find. Now, here were in a crowd forest in the andys in peru so youre looking down a ridge from the very high andys from about 12,000 pete. And some scientists here, scientist named myles soman works at Wake Forest University laid out tree plots along this ridge. At different elevations, and each of those plots is about 2 and a half acres exactly 2 and a half acres and in these plots you can get up to 100 different species of tree in just two and a half acres. So five times as many species as you get in a billion acres up in canadian forest that shows you theres a whole lot more species living in the tropics. And what theyve done in these plots is theyve tagged and measured and ided by species every tree with a diameter over o four inches. And this sort of leads to another reason why tropical species h as level and lose with Climate Change and much to lose as arctic species, that is that tropical species tend to inhabit these very narrow range, very, very specific climatic conditions so wz we were hiking down that ridge that i showed you before, myles said to me look, find a leaf. Find a leaf with an interesting is happen as we go down this trail. And watch it as we go down, and youre only going to see that this leaf for a couple hundred meters because that is the whole range of this tree. That is the only place youre going to find that tree. So theyre very well adapted to very, very specific conditions. And the whole point of his experiment an laying out these tree pods and measuring trees and tagging them is so see what happens to trees as andys warm and theyre warming very, very quickly. So to track the climate and climatic conditions most offing up the mountains by meters per year. Oval trees dont move, they get up and move but they do you know, put out seeds and then those seeds can survive at higher an higher elevations. And what they found, this experiment has been running for about a decade now and the earlier results some species, some species are moving fast enough to track the climate. But only a few. Most are not. And a lot are not moving at all. Theyre just sort of sitting there so these tree communities which had have tended to be very stable over time in the tropics because the climate has tended to be very stable, are going to break apart. Right, were going to have different trees moving at different rates. So what is going to happen to the creatures that are also adapted to living in these communities . Well that is a difficult question to answer. You know the insects, birds, mammals because it is really hard to tag for example an insect. Trees have the advantage, theyre easy to study because they stay in one place all of the time. But as myles pointed out to me, unfortunately were going to find the answer. Were going to find out what happens to these species because were running this gigantic experiment. And another question that arises in terms of what is going to happen to the tropics when you think about it. As all of these organisms move up slopes what happens in the tropical lowlands. Those are the warmest places on earth. They tend to have a lot of species there. But as everything is on the move, what is going to move into these tropical lowlands . Are they going to sort of empty out . We dont have an answer to that at this point. But unfortunately were going to find out. So Global Warming is not the only effect, though, of pouring a lot of c02 into the air. It has another very significant effect and perhaps some scientists would argue more significant effect. And that is what it does to the oceans. So here just are a couple of key facts about this. The oceans have absorbed about a third of this c02 weve admitted since the start of the industrial revolution. That amounts to about 150 billion metric tons. Every hour the seas absorb another million of c02 and the result is it increased by 30 . And that detail of this phenomenon which has become known im sure youve heard of Ocean Acidification are complicated and not beginning into the knity gritty of the chemistry but basically all you need to know is if you dissolve c02 into water it is an acid and you have an afternoon and