 Okay, welcome everybody. Very glad to have you join us here for the latest installment in our Earth Week programming. My name is Dan I am the director of development and programming for the bed for playoffs. I want to thank you for taking your some time out of your day today happy Earth Day. For what I'm sure is going to be a really great, great presentation. A couple of things very quickly before I introduce our special guest for the evening. To ask a question, which you can do at any time during the presentation. There is a q amp a button which is located at the bottom of your screen on your laptop or PC. It's at the top of your screen on your iPad or iPhone. If you post a question there will be time for questions later on in the program. I hope all of the students who are tuned in this evening I know it was an assignment but I think you'll find it informative please don't be shy about asking questions. The bed for playhouse is a 501 C3 nonprofit. So as always, we ask that if you enjoy this presentation if you find it informative. Please consider visiting our website bed for playoffs.org and consider making a contribution we cannot do it without the support of the community. We really appreciate all the help that we get any contribution is sincerely appreciated. I also lastly mentioned that we are recording this evening. So there will be a recording that will be available that will send out to everyone. For those who might want to revisit all or part of it or share it with anyone that you think might be interested in viewing it. It'll be on our YouTube channel. That link will also come around along with a few other links that are relevant to tonight's talk or for more information. So with that being said, let me read the introduction for our very special guest. Dr Alex Halliday is the director of Columbia University's Earth Institute. He joined the Earth Institute in April 2018 after spending more than a decade at the University of Oxford, during which time he was dean of science and engineering. The scientific achievements have been recognized through numerous awards, including the Merchison Medal of the Geological Society, the Bowen Award and Hess Medal of the American Geophysical Union. The URI Medal of the European Association of Geochemistry, the Oxford Medal of the Institute of Measurement and Control, and a knighthood for services to science and innovation. He is the fellow of the UK's Royal Society, an international member of the US National Academy of Sciences. As a professor in Columbia's Department of Earth and Environmental Sciences, Dr Halliday divides his time between Columbia's Morningside Campus and his Geochemistry Lab at Lamont Doherty Earth Observatory. The main focus of his current activities is establishing the new Columbia Climate School. Please welcome to the forum. Dr Alex Halliday. Hi. Yeah, thank you very much indeed Dan, very nice to meet you. Thank you. So, what I'd like to do is to talk with you today about the whole history of the earth in half an hour, and just quickly give you a sense of context for how the earth has changed and how much it's changed over its amazing geological history. And much of it we've had to had to piece together with something, a field called Geochemistry, I'm a geochemist, where we use techniques you called isotopes to actually make this happen. I'm going to share my screen to start the presentation. And there'll be one or two videos and and audios, they should work okay if there's any hiccups that can interrupt but I think it'll, it should work okay. I'm going to go to share screen. And there we go. Full screen. Myself out of the way. So I hope you can all see that okay. I want to, I want to mainly talk about the overall history of the earth today and how it's evolved, and why basically the last half of the talk is really about the more recent history of the earth, and how in particular it's changing, and in terms of the human influence, and why we need to decarbonize, in order to avoid dangerous climate change. So I'm, I'm not going to have time to talk about every aspect of climate change or the earth system here. Feel free to ask questions afterwards. And there may be a lot of things that I touch upon that might spark your curiosity to do with the evolution of the earth as well. So I'll ask questions about that as well, going forward. But I did want to talk about the end about how we're building the climate school this new thing it's the first school that Columbia's had for over 25 years, and it's a major step forward for us in terms of our ways with thinking of combating climate and contributing to the effort to decarbonize and transition society. So I want to include that in talking about the recent history of the earth at the end. But let's start with the beginning. Just to let you know that if you didn't know that we're made of stars which of course is a movie song or it's in a movie song but the idea that we're made of stars is actually correct. The carbon night should pretty much everything except the hydrogen helium that makes up our solar system came from other stars and was born in other stars. And one of the remarkable things that has been discovered over the last 30 odd years is that we've got bits of stardust preserved in meteorites that we have in our museums, and they are falling on the earth on a regular basis. They're actually the most common kind of meteorite that we have. And these are bits of early solar system debris that include a whole lot of bits of the early solar system, but they also include some of that original stardust that was formed around other stars. So that's another talk I can give you some time about how the solar system first formed. But these are the kinds of rocks that we're talking about they're not like normal rocks. They are called chondrites, because they've got these strange round things I don't really can see these things. These round things are called conjures they're about a couple of millimeters across very small, maybe half an inch maximum. They don't have to switch between American and European here. And that's why they're called conjrites because they've got these conjures. They're not rocks that formed like from a volcano or anything like that, or as a normal sediment. They're sort of rubble piles from asteroids, and they're asteroids that never got big enough or hot enough to melt. And so they didn't actually they represent the early dust of the solar system and junk of the solar system. It's a remarkable pile of junk because it's got the earliest history of the solar system preserved in it. And one of the most important sets of objects here apart from those conjures are these sort of really grubby looking gray gnarly looking bits which actually are called refractory inclusions is a bit more of one over there. These things are how we actually figure out the age of the solar system. This is my lab in that I had in Oxford, and it shows one of our mass spectrometers that we use for measuring the isotopic compositions of elements, and those isotopes. Those of you who are Rhodes scholars may recognize Rhodes house up window there. And those isotopes tell us about the history of the solar system, and also they tell us about temperature, which I'll come on to later on. So this is what you conclude about the earliest history of the solar system. And how long we've been around for this is. These are those really early objects that this first object down here at the bottom calcium aluminum refractory inclusions. These are thought to be we called them pebbles because they're thought to be very small objects that became slightly bigger objects and bigger objects. And this is how we think we eventually built planets from these things sticking together. And these are the ages of this is a uranium lead age has been determined, but there are others very similar to this of four and a half billion years. And these are the oldest objects that we know that formed within our own solar system. And we know their age you can see the error bar there. That's actually less than a million years, four and a half billion years ago. I'm incredibly precise. We know when the solar system started because of those early grabby little objects. We've also got those condoms they've got a range of ages that span a few million years. And then we've got meteorites from Mars, and we can tell from those the Mars formed in a few million years. Iron meteorites, which are the most common meteorites that you actually find. Condrites are the most common ones to fall on earth, but I am meteorites hang around with the condrites just fall apart fairly quickly. So very often when people come across something strange and field or a desert or an ice sheet, it's an iron meteorite, because they hang around for longer. And these are actually the metallic cores of early planets. And these things are, you know, less than a million years old in some cases. They formed incredibly early, the very start of the solar system. So within a million years we already have planetary objects forming. They were less than 100 kilometers in size. They were and typically maybe the size of New York City or New York State, something like that. They weren't massive planets, but nonetheless they were big enough to melt and form that metallic cores, rather like the Earth is a quarter day but a very early form one of those. We can date those. We can also figure out indirectly the time that Jupiter and Saturn formed, which are giant planets by using isotopes, which I won't go into the details of it. But I think with the energy we know that there was in the early solar system for melting and how it affected some of the icy satellites around some of these objects, and that tells us roughly how much energy there was. And therefore, when Saturn formed, for example, so that gives you an idea of how quickly the earliest objects formed in our solar system. That's the first roughly five million years of the solar system. Now I want to show you what happened with the formation of the earth. And here the time scales change quite a lot. So down here, you've got what's happening to us neighbors in the bottom. And this time scale is now 250 million years we've gone from eight million years to 250 million years. And this is the early planet formation I just showed you. There are certain things happening on other planets like Mars, for example, we've been able to figure out. But this is the growth of the earth, which we've been able to reduce. And it's quite gradual by comparison. And in particular, we think that the last big chunk of earth formation what we call in the giant impact here, which is the last 10% of the mass of the earth. Which is when the moon formed, didn't happen to about 60 or 70 million years after the start of the solar system. So it was relatively late. There are one or two things that came along later, which are called late veneer. This is this late veneer is very interesting because it's the reason why we have some gold and platinum in the surface of the earth where we are today. Most of the earth's platinum and gold should have gone and did go into the earth's core. If you took the platinum or the amount of gold that's in the earth's core and made it a layer of gold around the surface of the earth. It would cover the earth to a depth of a meter. There's a lot of three feet. There's a lot of gold and platinum all there in the core of the earth. But there's a little bit, which is the stuff that we use in our jewelry etc, which is actually in the silicate part of the earth where we walk around on. And that was probably added in this what we call is late veneer after the core had formed. That's why it didn't go into the core. And that's why it's so, so really amazing very interesting thing. And then we've got some things that happened on the moon which are added in down here, just here I'll come back to this in a minute. These are the oldest grains that we found on the surface of the earth. The Jack Hill circles, and they are they've been dated at 4.35 billion years. So they're roughly 200 million years after the start of the solar system. These are the oldest grains that we found that actually formed on earth, and that we can much of the early earth has been destroyed and the surface of the earth has been destroyed. But this is a bit that we've got that's actually there. So some of these grains that formed on the surface of the earth from from rocks rather like our continents. So I want to say just a little bit about this moon forming giant impact because this is actually quite important. If you want to talk about temperature on the surface of the earth. This was temperature like no other. The moon forming giant impact was between the earth, when it was only 90% formed, and another planet that we call there. When it was about it was about 10% of the mass of the earth or roughly the size of Mars. And this is a fair because I asked my team when I was in Switzerland, who was the mother of Selene, the goddess of the moon, because we need to know who gave birth to the moon, and it was this goddess fair who basically gave birth to Selene so we basically decided to call the planet fair. This is an in simulation of what that look like that giant collision between these two planets. And it's been done by my colleague Robin cannot, who I'm writing a paper with right now she and I work on stuff to do with the early system when I'm working on those things. This shows those two planets getting closer to hitting each other with a glancing blow. And you can see the energy that's involved in this this looks like a cartoon or something that may have been done. You know just for fun, but actually it's a very high resolution powerful supercomputing simulation, and it gives a rough idea of the temperatures involved. And those temperatures are huge. I mean the thousands of degrees that the earth is being heated up to. So you wouldn't have had a water atmosphere or a steam atmosphere, you would have had a rock atmosphere you would have vaporize the rocks of the earth to actually form a sort of super atmosphere which you have around that glowing planet. I'm not happy, I'm not happy with how slowly it's going. But anyway you get the picture. And anyways from this, the debris that was left, going around the earth that we formed the moon. So that's one of the most interesting areas of discussion these days, exactly how it happened. What's important is because we actually think that the moon, and that giant impact gave the earth, its spin. The earth's moon provides an anchor and stops the gravitational anchor and stops the earth from from wobbling too much. And of course, the moon also gives us a tide, it gives us the tilt gives us seasons, and we think all of this was actually really important from the point of view of forming life on Earth, and for life to actually develop in a habitable way, and a stable way. We think the tides may have been really important from the point of view of a one time eventually getting vertebrates to develop, and for amphibians to come out and walk around on land. That's another story again, some other time we'll tell you about that. So, let me just get back that's the moon forming giant impact. I just want to talk quickly about these Jack Hill zircons a little bit more, which formed 200 million years after the start of the solar system. Because this is an example of some of the oldest crust on earth here. These are four billionaire rocks. There are no rocks you can walk around on that are older than these there so there's, I said the solar system four and a half billion years old. And the oldest rocks you can walk around on on the continents are four billion years old. So the first 500 million years of the earth's history at the surface of the earth is missing. It's been destroyed. And those unlike on the moon or Mars, where we've actually got rocks that are from the very earliest history of those planetary objects. We don't have that for the earth. Everything's been decimated and destroyed on the surface of the earth. So, four billion year old rocks. What's interesting about them is that the ones these guys are walking around on are actually sedimentary rocks, and they tell us that they were laid down in water. So that means that there was water, liquid water on the surface of the earth by about four billion years ago. So I've got here these Jack Hill zircons, which are found in Australia, they've been found in earlier settlements so they're grains that are older. Sorry, they're not earlier they're younger settlements, but the grains are older they basically been brought down from erosion from earlier constant or rocks. And what's been found is that actually these grains are 4.335 billion years old. So within 200 million years or about 200 million years after the start of the solar system. And the isotopes in there of the oxygen in particular, tell us that there was liquid water on the surface of the earth, even then. So that cooled down within about 200 million years, and there was liquid water. We went from that very hot state to something very cool. Where there was liquid water on the surface of the earth. So those oxygen isotopes are really important. It's a technique that was developed by a guy called Harold Yuri, Harold Yuri, won the Nobel Prize for discovering deuterium. He was a professor of Chicago, and he also then went on to do all kinds of things about the origin of life. He had all kinds of work he did on the origin of the moon. But one of the most important things he did was to realize that the different isotopes of oxygen that's for those of you don't know isotopes have the same place in the periodic table. They don't affect the oxygen atoms, but they've got different proportions of neutrons and because neutrons are neutral, they don't affect the chemical properties at all. But they do affect the mass, and that the proportions of one isotope of oxygen relative to another in a carbonate, say that's growing from seawater, like for example, a seashell growing from seawater. The proportion of oxygen atoms, the isotopes tells you how cold it was or how warm it was. And this is the key to figuring out the entire temperature history of the earth and how it's changed over time. Now, I just told you there was liquid water on the surface of the earth. In these very very early times. What's interesting about that is that the earth actually should have been frozen. Most of you probably know who was a very famous scientist, he died very early unfortunately. But he was a brilliant scientist and great science communicator. He posed this problem that actually stars when they start up. It takes them a while to really heat up. And our sun would have taken a while to get to the kind of temperatures where you would have had liquid water on the surface of the earth. And the sun's energy wouldn't have been sufficient for water to form on the earth, except as ice. So on the surface of the earth, we should have actually cooled down even more from that moon forming giant impact. So that's really interesting and it tells us that must have been something in the atmosphere that was keeping it warm. And that thing was probably carbon dioxide. It may also have been methane or it may have been both. But we had what we call greenhouse gases in the very early earth, and they were essential to keeping it warm. Otherwise, we never would have had liquid water on the surface of the earth. And of course greenhouse gases we talk about a lot today, because they keep the planet warm today. And the same is true today if we didn't have any greenhouse gases at all water was a greenhouse gas actually. But the these gases basically at some level provide both sustenance for the planet keep it keep it habitable, but also they can actually heat it up too much as we'll talk about in a second. So using these oxygen isotopes again, they need to know the details of how we do it. This is a rough idea of how temperature then changed on the surface of the earth. Between roughly the earliest signs of life we've got some micro fossils that formed about three and a half billion years ago. And we've got more of those going over over the history of the of the earth, until about 500 million years ago when suddenly things exploded and we had lots of diverse life forms. We've got estimates of temperature based on oxygen isotopes. And we see that the temperatures for the various things that we've got mainly. They're what we call opal, which is like silica it's it's kind of like, like quartz but it's not crystalline like quartz, and you get open in the oceans and you get it open back through time in some of these rocks. So the temperature of the surface of the earth from the oxygen isotopes in the opal, and you can also do that with carbonates as I've already said. And you get temperatures that are actually quite high, much higher than today today we've got down here on the right we've got the present day average surface ocean temperature about 15 degrees. You can see that back in those days temperatures are way warmer. And it wasn't till temperatures got much much cooler, and more like they are today that we started to see the explosion of diverse life forms that are actually the main invertebrates the brachyopods the trilobites the bivalves, as well as vertebrates starting to develop around that time. We're not going to quickly whiz through the rest of the history of the earth, and just give you some idea of just how much temperature has changed on the surface of the earth, of course not like the thousands of degrees of the moon forming giant impact. But nonetheless, we've had some big temperature swings, even in the last 500 million years. Again, not as much as we had, you know, in those very early life when there were those very early life forms. There were temperatures of about swings about 10 degrees or more over that period. And this shows you the last 500 million years. You can see the temperatures went up dramatically. And at times there were more than 10 degrees warmer than today. At other times they were much lower. And, and that gives you some kind of a rough idea of how things have changed over time. This time at the end here, about 65 million years ago is when the dinosaurs went extinct at the end of what we call the Cretaceous, and we get into a period called the Cenozoic shown in green here. So we're looking at this now in more detail on the right. We call that the Katie boundary when the dinosaurs went extinct partway through the bit on the left. We have the whole development of amphibians, life on earth, various kinds of plants, amazing things happening that again are, you know, some level related to the formation of the moon. But this bit since 65 million years ago since the dinosaurs when extinct. Relatively stable surface to the earth. Things have been going quite strikingly in the direction of cooler and cooler temperatures. So there are some exceptions that I'll talk about a second. But what you can see is over these last 65 million years ago this this 65 million years, this basically takes you through to about 5 million years ago. You can see that the temperatures start off incredibly high, like again there are about 10 degrees Celsius relative to today. And there's a peak here at about 14 degrees, which is thought to be written is about 50 million years ago, which is thought to be to do with a, when the oceans got so warm that some very cool methane hydrates methane deposits, pathways at the bottom of the ocean erupted, they came to the surface, and a ton of methane was added to the atmosphere, which, as you know, is just a greenhouse, a greenhouse gas. And so temperatures went even higher during that early. What we call palisthenic, you're seeing thermal maximum. And then things started cooling down they've been cooling down getting cooler and cooler. There have been some times when they didn't go up and down just went flat. And then they got cooler and cooler and cooler again. So let's see how we then go into this period of the last five million years, when things are even cooler that trends continues. And over this time of cooling of the surface of the earth, things have changed dramatically. So, back at the beginning here, 50 million years ago. There were white sheets on the surface of the earth Antarctica was barren wasn't barren it had probably had quite thriving forests on it and there was, there are wild animals rolling around roaming around the same in the Arctic as well. And it wasn't until about 35 million years ago that things got cold enough that glaciation started in the Antarctic. We see the beginning of Antarctic glaciation because of the kinds of deposits that get preserved in settlements around Antarctica out in the oceans. Of course they weren't penguins that are just like that photograph of penguins diving up. And then in the northern hemisphere, we started getting Arctic glaciation northern hemisphere glaciation around three million years ago so much much later. It's a smaller amount of ice there's about one tenth of the amount of ice that form in the Arctic as there isn't the Antarctic or Greenland as there isn't the Antarctic. So Antarctic is the big beast in terms of ice. But nonetheless this is more of the same trend of cooling down surface of the earth. Who knows what started the ice age three ice ages in the northern hemisphere three million years ago, but of course the ice sheets eventually covered the extended right over New York City for example, and you can see the remains of their movement in Central Park. So things got cooler and cooler and cooler for quite a while. So these records I've just shown you are based on using seashells and things like that. And a few years ago, we came up with the most brilliant more accurate kind of method, just for the last several hundred thousand years. And this is from what we call ice cores so in Antarctica, it was decided to drill down through the Antarctic ice sheet, more than two miles. And we got down to, we're trying to get down to Lake Vostok, which is down below there I say we, it was the Russians with the Americans and the Brits and a few others who were involved as a big team doing this. And in the process they withdrew this core of ice, which of course is still preserved. It's the Vostok ice core. And we can actually get that there are little bubbles, tiny bubbles of air trapped in those, those ices. And we can actually get the air out, and we can measure the carbon dioxide concentration, which is remarkable. You can also tell a lot of other things as well. You can tell from the oxygen ice strips in the ice, what the temperature was. So you've got this record of how the earth was changing through the ice ages from this amazing glacial interglacial period. I won't go into the details of how we go from glacial into interglacials is to do with the way the earth processes and spins. But basically every hundred thousand years, we've been going from a glacial environment to an interglacial environment. And this shows you how much carbon dioxide there is in the atmosphere during glacial times when the surface of the earth is cooler. Carbon dioxide is more soluble in ocean water. So more of the carbon dioxide goes into the ocean and less stays in the atmosphere, whereas in interglacial times you get these peaks, where you get carbon dioxide around 300 parts per million, 280, 290, those kinds of numbers. And that's basically the way things are, and that's the way things should be today. We should be in an interglacial today, and with roughly 280 parts per million carbon dioxide. Now, in reality, this is what's happened instead. There's been this massive rise in carbon dioxide. You can see this in the ice core record. You can also, of course, measure it because we've been measuring carbon dioxide concentrations for decades on monolow in Hawaii and getting direct measurements of carbon dioxide going into the atmosphere. And those two records agree, those records agree with each other perfectly. So carbon dioxide is going into the atmosphere and increasing rates. It's an incredible rate. It's far faster than anything naturally, about 10 times faster. And it's having a major impact on the planet. And we know exactly what's causing it. So this is a blow up of that period. And you can see basically in calendar years here, towards the end of the 1700s. You actually get a significant increase starting in that level of carbon dioxide. And if you know your history, you may know that this is when the Industrial Revolution started 1769 a Scottish engineer called James Watt patented a new more efficient kind of steam engine. And this sparked the start of the Industrial Revolution. Of course, there are many other facets to it as well. It had huge impact on society. Of course, it was tremendously positive for people, lifting people out of poverty, creating jobs, creating well being, and many other things, but it also created CO2. And the burning of fossil fuels in particular has been driving that big change in CO2 in the atmosphere. So I just want to quickly go into now about what this means. And I want to introduce you to Columbia University's climate school, which is built on the legacy of some amazing climate scientists at Columbia, in particular, Wally Broker. Wally Broker this here is with Bill Clinton getting the National Medal of Science. He's one of the probably the most distinguished climate scientists the world ever had. And he was here in New York. And in 1975, he introduced the term global warming into the scientific literature. And I just want you to hear one of the things he said back in 2014. He died a couple of years ago, unfortunately, but this, listen carefully to what he says. I'm not going to use projections. I'm going to try to scare you a bit because I don't think that many people really get it as far as how difficult a problem this is. This is an awesome problem. And people who don't want to believe it at all, but a lot of people who are aware and accepted it is a problem, don't really get it as to how serious a problem it is. It's really, really bad. I'm not going to use projections. I'm going to try to scare you a bit. Okay, so I just wanted to quickly. I mean his voice is pretty important because he was one of the early people who warned about global warming and the effect that it was going to have on the planet. And in these later life got more and more pessimistic about our ability to deal with this. And so of course today is a great day because the Biden administration but other world leaders as well are getting together to make a strong pitch for trying to deal with this carbon dioxide problem. So let me just quickly explain to you why we're doing this at Columbia and focusing on this problem. It's not just Wally Broker. We have a top ranked for Geosciences. We have close to 1000 faculty researchers and staff who are working on climate sustainability. So we're unusually strong in that particular subject. And the body that I direct to the Earth Institute has over 20 centers including the month of the Earth Observatory which is shown here on the right, and which runs the Lancet ship which is one of the global class and vessels. We've done a lot of work and we have been working on the oceans for many years, but on Geosciences, Joey, we're also strong in a number of other key disciplines like journalism, energy, engineering, etc. So, but we also have a strong connection with NASA Goddard Institute for Space Studies. So that's another reason why, which I'll come on to in a second, as to why New York is such a great place to be studying us. So what we're doing are understanding and modeling the climate, trying to figure out what needs to be done to slow down climate change, and policy work that needs to be done as well as the technology that needs to be developed. We're interested in, of course, resilience and adaptation. And then finally we're interested in climate communication and how do we change people's ways of thinking. So we've got a bit of Tom's restaurant, because we're rather famous TV series. Well, you may not know that Tom's restaurant, this building is actually owned by Columbia University. And on these in these floors above is the NASA Goddard Institute for Space Studies. So NASA Goddard Institute for Space Studies was run by this guy Jim Hansen, and he's still around he's in the Earth Institute with us in Columbia. And he was one of the key advisors to the president of the United States on science, and he became aware of the issue of global warming and today he's a massive advocate for this. He's long been trailblazing in warning people about the worries of global warming. The NASA Goddard Institute for Space Studies which is shown that their climate record is shown here. They, along with many others that I could show you the Hadley one from the UK, or I could show you the Berkeley one. They all show the same curve for how temperature is changing. And it's quite dramatic. It's been going up pretty steadily. The detail are ups and downs from one year to the other. Over the last 50 years or so, it's been particularly striking going forward. And we have a very good idea how to measure temperature now. All the all the records, the different groups trying to come up with different estimates. They all agree about it. It's initially quite a difficult thing to do. How do you measure an average temperature for the earth surface temperature for the earth. And we've got very, very good data for it today. I just want to show you some of the effects of that. This is shows you what's happening to Antarctica today in terms of those ice sheets. And this is work going on at Columbia's observatory, and it shows you how ice is flowing off the continent. It's actually flowing out into the into this area here into this estuary, and then disappearing out into the oceans, it's melting. The temperature change is being shown here. The dark as it gets darker over time these is this is changing every year. It's getting darker. That means the elevation is going down. We can measure this for satellites, of course. So we're losing mass of Antarctica into the oceans, and it's very, very dramatic. This is a, which was published by a colleague who's in Arizona. Sorry, in California. Rino et al 2018. This shows you. They've come up with estimates for roughly four decades of ice loss in Antarctica for the Antarctic ice sheet. And this is expressed in gigatons per year. A gigaton is a billion tons of or trillion, a trillion kilograms. And roughly speaking, if you want to see what a gigaton is, but down here in this little box, one gigaton is 400,000 Olympic pools. So this has gone up quite dramatically and see the numbers here. And this most recent decade, looking at 250. 250 gigatons. So we're looking at looking at 100 million 100 million Olympic pools being lost every year from the surface of the earth as melting ice into the water. And that of course is affecting sea level. And this is also work that we've been very heavily engaged with. And it shows what's happening. You can't. The earth is not a bath tub. It doesn't actually just water just go up and down. If you take ice off the continents, like Antarctica or Greenland. Actually, the land underneath goes up because you're taking the pressure off the surface of the earth. And so sea level in places is going down. So the average sea level change doesn't tell you what's happening in detail. In some places mainly around the equator are more at risk than others. And these big red arrows are particularly important for the yellow ones aren't so great either. And that includes the south and east United States for example. If you go back to when we had 400 parts a million of carbon dioxide in the atmosphere naturally, which was before the ice ages three million years ago. The sea level was more than 50 feet higher than today. Many coastal cities will be completely flooded. These are some of the cities that are most in danger of sea level change. It's not just the sea level change itself. But what happens during a storm of course like Hurricane Sandy that has a big impact. If you hit Mumbai, the in India, the effects will be far worse. But I just wanted to highlight the fact that these top 10 cities in terms of population and vulnerability. Five of them are south and eastern United States. So we're doing a lot of work in Colombia on trying to understand this. And in particular, we've been getting people to think about how do you retreat from coastal areas. We did a conference a couple of years ago. It was a knockout nobody ever heard this term managed retreat before. There were more than 50 journalists there out of 300 people. And we're doing it again this year. We're course going to do it virtually. We don't just work on adaptation and these major issues about how we adapt to climate change we also work on decarbonization this shows you what we've got to do in terms of greenhouse gas emissions. It's kind of complicated in some ways don't worry about it. But the key thing to realize is that all these emissions here the biggest ones are carbon dioxide, in terms of their, and their contribution. The biggest cause of this is energy, which is shown here on the left. And there's a lot of things that you need to decarbonize to make a difference there. The problem is that, while we're increasing the proportion of renewables. So this shows you the proportion of renewables, and how that's growing over time. You can see renewables becoming more and more important over time. The trouble is, the proportion isn't the key thing. What matters is the denominator, the bit on the bottom, which is the total amount of energy that's being consumed. And as lifestyles improve people want to, because they're getting wealthier, healthier wealthier living longer, wanting to have more things when they have their own car. And so the total amount of energy consumption is going up dramatically over time as you can see on the right. And if you look at the gas oil coal and biomass. It's projected to carry on increasing, despite everything we've been doing with renewables. That's why we have a massive problem on our hands. All the work we've been talking about to do with climate change switch to renewables decarbonizing the planet. We're still putting carbon dioxide into the atmosphere, and the energy mix that we're putting together, even though it's a greater proportion of renewables isn't enough to offset the fact that there's a bigger energy demand over time. This shows you one of the things we need to do to deal with this because this is greenhouse gas emissions and gigatons of carbon dioxide per year on a Y axis, and how that's changing expected to change over time. If you have business as usual, shown over here and just efficiencies that start to come in. What happens if you want to get below two degrees Celsius warming we've got one degree so far. But you might and of course what we've been told is we should get below that even further to 1.5 degrees Celsius warming. These options for trying to reduce carbon dioxide in the atmosphere. We can't do it just by switch to renewables we actually have to take carbon dioxide out of the atmosphere. And that's what we call negative carbon dioxide emissions that show here. We've got to figure out ways of getting carbon dioxide out of the atmosphere and bearing it underground. So a lot of work on this going on it's going to be a key part of plans for America and other parts of the world going forward. These are four individuals at Columbia University from different centers, all working and producing work in this particular area on how we actually take carbon dioxide out of the atmosphere. And just very quickly because we're running out of time. It's actually really important from the point of view of real live experiments the president of Iceland working with Wally broker and others many years ago. We started this project of the Earth Institute to actually try taking carbon dioxide and putting in solution water and getting into rocks and mineralizing it underground. And actually it works. We find that we can actually get carbon dioxide and store it underground. Bluebird Bloomberg today, Iceland startup wants to turn carbon ship from Europe into rock they're going to turn this into a way of getting rid of carbon dioxide and putting it in the ground. They expect to be able to run about 3 million tons of carbon dioxide, turn it into rock by 2030 just to remind you the numbers I just showed you of how much carbon dioxide we're putting into the atmosphere. 3 million tons a year. It's 50 billion tons of carbon dioxide a year. So this is a small important step, but it is a small one and we need to do something much bigger. There's also there are many other examples of this when people are trying to capture the carbon dioxide from the air. This is one in Switzerland. But there are several others starting up around the world as well, trying to take carbon out of the atmosphere and then figure out how to put it underground. So just to finish. I know I've talked a bit longer than I expected. I just wanted to summarize and I think there are reasons to be positive. And of course it takes a lot of political will. But we do have the science and technologies. We do need more. These things are still very expensive to do we need to make them cheaper. So political will ultimately politicians are elected on the basis of how they keep people happy and so if you're not making people happy people won't want to reelect you. So political will has to be gained here by talking to people and communicating with them about how important this is. We can mitigate climate change but it requires not just technology but also policy and strategy to do that. And the role of young people in particular I think they've had an incredible energizing effect. This is the biggest intergenerational human rights issue that we face. And we have to worry about not how inconvenient things are for us, but what we're going to be doing to our future generations and their ability to live on this planet going forward. So thank you very much. Good to talk to you. I'm just going to stop sharing. Okay, great. And I just a reminder, anybody who'd like to ask a question please use the Q&A button at the bottom of your screen. We're going to start with one that actually was submitted by email and it's in two parts, which is kind of interesting. One is, is it true that in the early months of the pandemic there was a noticeable drop in atmosphere carbon because no one was leaving their homes. And the second part of that is, do you consider that to be positive because it showed that there is something that can be done, or is it a negative because it took a global pandemic to prove it. I don't think it was positive or negative. I think it's interesting to see when you, well I think it's interesting to see that carbon dioxide emissions come down. It's not surprising. People aren't flying so much, people aren't using so much energy, they're not getting around in their cars so much. They're not actually even using their offices so much, they're actually all staying home. So there are a number of ways in which and of course a number of companies had to just slow down or even effectively stop for a while. The whole economy has been impacted by this. So it's not surprising you see an effect on CO2. The problem is that massive, you know, collapse of the economy that we've seen globally actually didn't have much effect on CO2. It had a relatively small effect on CO2. And of course, you know, coming out of the pandemic, we know that things are going to be much higher with the vengeance. People are going to be working like crazy, trying to rebuild their economies, carbon dioxide levels are going to go even higher than they have been going forward. So I think it's, you know, I think it's not a positive or a negative. I actually think that it's a statement. I think one of the other interesting things is about the pandemic is that it demonstrated the fact that two things. And the other thing is governments find it quite hard to deal with this in different ways. They don't actually know what to do all the time. And they, they're trying to get advice but they've got to bow to the political will and the financial pressures on the economy and all that stuff. So they don't know quite when they're open and closed. The UK has been all over the place on this, going backwards and forwards and opening and closing. There are different responses around the world. If you look back at the flu pandemic 100 years ago, it was exactly the same and certain places closed down dramatically, and fewer lives were lost. Other places tried to keep going, and they didn't. So the lack of coordinated global action is quite striking in this pandemic. It's quite striking. Actually, the same is rather true around climate change, trying to get people to all act in the same way, particularly in the context of human, human response, what people, what people think about their, their, you know, their livelihoods people and their livelihoods decimated by a pandemic. So, or their way of life. So they basically want don't want to wear a mask they want to carry on, you know, going out going to the movies and all the rest of it eating out. And so despite all the public health warnings, and despite the efforts of some people, there's a human factor that you've got to get hearts and minds on board support what you're trying to do. Otherwise, people will lose their lives. And it's the same a bit with climate change. Nobody wants to lose their jobs, nobody wants to have more inconvenience by switching from gas to electric cookers. Nobody wants to fly less people like to eat steak, all these kinds of things. So how do you actually deal with those things about a lifestyle we all like. And at the same time, decarbonize the planet. And that that's where a lot of the political will. You've got to win people's hearts and minds. And in particular, we've got to think about jobs and communities like coal mining districts, they're going to be decimated as a result of closing down coal-fired power plants, etc. So that's, that's a big thing I think Biden's got right, the Biden administration's got right. And I think that's hopefully going to be do a better job of deep decarbonizing America in the past. So we have two questions that are sort of related to there about more current events. You just referenced actually the news today about the US proposal to cut emissions, 50% below the 2005 levels. And the other question, Elon Musk announced today, the largest prize in the history of prizes, 100 million for the best carbon removal initiative, and the winner must build a prototype that removes 1000 tons of carbon a year. What's, what's your reaction to that? Well, I think, you know, I'm a big fat, I mean, I know Elon Musk's a controversial figure. I think what he's trying to do is really exciting. And if you look at the technology he's developing, and he has developed, I think it's spectacular. He's an individual with fantastic vision, and I love his vision for spaceflight just as much as I love his vision for renewables and trying to switch us to electric vehicles. I think it's all brilliant. Despite what you might say about other aspects of what he tries to do. I think trying to get people to think about some of these major challenges and offer big prizes. I think is a really good thing to do. I also think that for some of these technologies, there is a, there is a really, there is a ton of money to be made anyway. The technology is going to be so important and valuable going forward that we're going to actually be able to think about how can you actually build businesses that are going to work on the back of the so I think there are big opportunities for entrepreneurs, regardless of a gift from Elon Musk to build the technologies for the future that are going to make a massive difference. Today we tend to think about, you know, the oil and big oil states like the Middle in the Middle East Saudi Arabia for example. And we think about the monopoly they have monopoly but the strength they've had in terms of geopolitical power as a result of being in charge of so much energy. In the future, other states may have geopolitical power because they have great leverage with respect to renewables. So you might ask where, you know, the lithium lithium ion batteries comes from what comes from South America. And so some of those countries might actually become much more powerful going forward, and they can actually, to some extent dominate the landscape. But not just the individual entrepreneurs, it's actually government should be thinking about how can they really capitalize on this. I know that sounds like a sad way to think about a global crisis and people's health, but frankly, the economy tends to drive an economic opportunity and a lot of what really changes society these days. And so I think we should, we should look at those incentives and think about what can we do to facilitate more change through those. There's a follow up brief follow up to the announcement about the Biden's goal today do you think that it's realistic to reduce carbon emissions by 2030 as he's outlined. Well, so the, of course, I'm wildly optimistic you've got to be optimistic and and there are ways to do it so there's a part of me, depending on who you talk to. It's actually really almost like, how do you want to spend less. You could probably decarbonize. 50% of our energy and our carbon dioxide emissions relatively easy, it wouldn't kill us to switch to induction heated cookers for example, and and then have so we got cheap solar, we got cheap when you've got to set up the infrastructure to make that happen. We're building more effective longer term battery storage now we're starting to use figure out how to harness hydroelectric better. There are a variety of ways in which we can think about how to switch to renewables. Some of those switches may involve some changes to the landscape we can see a lot more wind farms, solar panels, big new infrastructure involved in getting the electricity across the grid. But we can do it relatively easily, but then you think we'll actually to get beyond the 50% we need to do actually much to get to carbon neutral. You've actually got to think about how do you decarbonize agriculture how do you decarbonize flights and and you know Boeing has said it's going to come up with a way to do it, which is quite remarkable. You know, people are interested to see how that's really going to work how are you going to decarbonize shipping, how are you going to decarbonize manufacturing, you know, steel and cement, these are incredibly, these produce a ton of carbon dioxide, more than a ton of carbon dioxide emissions. And so I think the figuring out how you're really going to do this. I think is is immensely important. Now there are technologies there are incentives. I think some of the incentives can be particularly effective the Europeans have come up with a green deal, which is going to be going to include carbon border taxes. So if you import from abroad, you'll be taxed if you haven't got a low carbon footprint on your product that you're making. So people can start thinking in countries beyond Europe. Hey, this is going to affect my business. I need to be thinking about how I do this. So I think there are incentives you can think about that could drive this whole thing quite in quite a dramatic way. I think it's going to come from regulation, exciting new infrastructure people actually enjoying living in a cleaner environment and things like that. I'm not confident. I am optimistic about the possibilities. Very good. Okay, so we're going to we have time for two more questions. So I'm going to ask, I'll ask them separately though. In the room seems to be population increase and consumption. How is that taken into account. How do you deal with an issue, a sensitive issue like that. In your opinion. Yeah. So, I think you have to, of course, consider it as a great thing that people can live longer they can work longer. Because, you know, people are, you know, are, you know, running companies when they're in their 80s and 90s now, and it's actually great that people have that ability, and it's a sign of the fact that we're living healthier lifestyles, medical developments and made a big difference. So that's a great thing. And of course, lifting people out of poverty to allow them to lead longer lives and enjoy life more. I think it's fantastic as well. So the last thing you could possibly think of is that it's a bad thing that people live longer, or it's a bad thing that as a result of that the population goes up. But that's where most of the population growth is happening it's from people living longer it's not from people having more children. And that is the key thing that you need to think about I guess is as we lift the world out of poverty, we're going to head towards larger numbers of people on the surface of the earth. There are some models that suggest it'll plateau. But that is kind of what we got to deal with and quite apart from climate change. We've got enough food on the planet of the right kind to feed all those people. So the, we've got we've got enough food. We've got too much food of certain kinds, but actually nutritious food isn't enough. We've got to build new ways of generating nutritious food. So we're doing all this at the same time as the bread basket to the world around the threat from climate change. And of course, it's not just going to affect areas like the Far East, where people are wondering about how to build more resilient rice, going forward and more nutritious rice going, going forward. It's also places like Southwest US where crops may have been used for feed for livestock, soybeans, etc. So it's either Southwest United States either that stuff gets exported to the UK. And so cattle farmers in the UK, actually getting their livestock from their feed from elsewhere in the world. So this is an incredibly interconnected problem around food security. So we haven't got just got a problem that relates to climate change and the risks of extreme events. We haven't just got a problem that relates to how do we decarbonize. We've got a huge problem around food security and having talked about health issues as well, which is another big issue going forward. So we're going to close with this question which I think is sort of pressing you mentioned you talked a little bit about being optimistic and hope. So the question is that the overall problem seems to be so intimidating. What can the average person do realistically do to reduce their carbon impact that is not so intimidating. The first thing you have to do is to vote. People have to get on board with this. Not just as something that is important for them but also important for their children and grandchildren. And what kind of a world do they really want there to be in the future. And of course you could talk about many other issues to do with biodiversity loss and other ways in which we're trashing the planet. But unless we make this a major political issue where people get to realize that regardless of whether you're a Republican or a Democrat, you believe that it's important for humanity to enjoy a decent climate in which to live and the safe environment in which to grow up. Then if you know what's got to be a massive political issue. And because these things are so long term they're sort of building up over decades. There has been a lack of political mobility on this, but actually people are starting to see things like massive wildfires on a scale they haven't seen before, a greater increasing frequency of severe storm events, hurricane Harvey, dumping water than anybody ever seen before in one of those major hurricanes, it was a new meteorological phenomenon, the climate is changing and people becoming aware of it, and they need to vote. And that. So that's the most important thing that any individual can do. I would say, you know, I think the other things to think about clearly things like switching to electric vehicles, if you can do that. You need the infrastructure to make that practical. There's no point switching to electrical electric vehicles if you haven't got placed on the streets to charge them up and keep them charged. If you go away for a week and come back and find your batteries dead, because it wasn't hooked up. Then what do you do. So there's a lot of infrastructure that's got to be built and nonetheless that move to renewables is going to be hugely important. And I think the last thing to talk about really is, we've got to figure out better ways of land use, and that includes an agriculture in particular. So we've got to because that's a big chunk of the issue around carbon emissions that isn't probably dealt with yet, which is good. It's going to be tough, really tough. But we've got to figure out how to change our land use so that it's actually better for the atmosphere, better for biodiversity, and actually better from the point of view of food as well. Food that is actually more sustainable and actually healthier going forward. All that needs thinking about quite a lot going forward. So those are the things I would think about apply pressure on those friends. I want to thank you very, very much for your time this evening. This has been great. I just want to remind everybody who's listening in we are going to send around the recording. Alex, if there are any links to the Earth Institute website or any other information you'd like to share, we will include those in the email. Okay, we'd love to have you come back and do the solar system talk. I'd sign up for that one and we can actually hopefully sooner rather than later we can do it at bed for playoffs, as opposed to to the zoom forum. Thank you very much again. And anybody who would like to post a question. After the fact, we will make sure that it gets addressed as best as we can. And have a great night. We really appreciate you're taking a few minutes out of your busy schedules for us. Have a good one everybody.