vaulting ambition to safeguard humanity against a major threat with the troubling hazards of following this science is recipes that's exactly what i think we have with geo engineering we have vaulting ambition we have a major threat we have give you the basics of the book very quickly and then have to run through some images that help us think about this because this book although it has its argumentative side is not really just sort of one big argument for or indeed against geoengineering but it's an exploration of why is the geo engineering can have meaning and so as it goes into the science and technology that underlie the various approaches that are now being mooted but it it goes a little it's a little bit more ambitious than that in some respects and probably more  believe as i have that the possibility of decarbonise ation of a form that is radical enough and just enough to cause tail those risks is very very hard to imagine  is an economy of seven point three seven point four billion people tied together by the use of fossil fuels which provide well over eighty percent of their energy needs it's very hard to see how you quickly remove the f fuels from the picture and so if you think that it's both important to address the risk of climate change and difficult to do something about fossil fuels in the in the near future then you have to face the question that you might need some broader options with the issue now i dealing with responding to i try although i flip in my language as we all do sometimes i try not to present geoengineering as a solution but as a response i don't think climate change is something simple decouple the climate future from the cumulative emissions to date that's the key point that's holds together very different forms of geo engineering and i think that puts helps you see some of the emotional potential and the emotional distress that can come in these discussions there is potentially something very liberating about the idea of being decoupled from the past being unshackle of emancipation from that which is already your lot the respect of the past is very important to us and i mention this just to point out that when we think about the climate we are always also thinking about our own emotional our own personal lives when we think about the technological way forward in the climate we shouldn't either embrace it or necessarily distrust it because it feels like making a big gesture in a personal life so that's th of essence of the book i suppose and i want to break out a few specific bits of it and of some specific images we'll take away the book just down to the images and was like where the images and go down to this which is something that i saw yesterday when i was on my way to so this is part of what fossil fuels do to the world they've expanded the world up to the higher level in the atmosphere they've also changed the world immeasurably in just a century of the beginning of the twentieth century though about one point six billion people on the planet there were three billion edirne as last year seven hundred fifty million within and to the united states three billion globally quite an extraordinary figure out of seven hundred fifty million tons colonized with our jet planes on every day jet planes this is up there at the edge of space you can see that you can see the blackness at the top of the picture this is a different experience it's a different sort of atmosphere the atmosphere in the lower atmosphere where the weather is th on christmas eve in one thousand nine hundred sixty eight and here you are completely abstracted although you can see that that's a very interesting planet best particularly compared to the dull one in the foreground you can't see any features on it anymore you can just see only the processes you're now on a planet incidentally that's completely dominated by its weather as far as you can see the clock around this time used to joke that if the earth of been discovered space they would have called it ocean because it's mostly ocean but in fact in terms of the lights is this is the rising moon this is a painting by thomas cole who was on the founders of the hudson river school of landscape painting in one hundred centuries of america this is the the end to understand the relationship between humans and their landscape and coal in this case is looking particularly at the landscape and human time and landscape and so here you have the wreckage of a human from the book that part of what made the industrial revolution steam engine so world changing was that they changed the world around them not just mechanically economically and objective really they did so subjectively to people started to see the world as not merely containing these strange new devices but as being one of them and this is this is another one of terms great steam paintings this is snow being moved and changed and changing the people within it because of this extraordinary application of energy to the environment which starts in the nineteenth century here is a much less artistic  needed to generate some power in orders runs and printing presses and printing processes and so he decided that the way to do this was to map out energy and so he mapped out the flow of energy through steam engines using these diagrams and using the rather magnificent is that almost all the stuff going in at the end as i mentioned that big meaning of the talk is fossil fuel stuff are the green stuff of biomass down here we've got nuclear renewables this is about five years old but really the differences would be pretty hard to see at this level one of the reasons why i think that simply removing fossil fuels quickly and easily from the picture is not a very realistic option this is not to say and i think i don't know if i stress this enough i'm going with not so i don't think it's a it's an important part of future action i really do i think that there's no way but this works that anything good comes out in different keep burning fossil fuels regardless i'm just saying it's difficult to get rid of them and very difficult to get rid of them quickly here is the problem if you make the atmosphere absorb more energy then this bit the energy coming back from the atmosphere gets bigger and this bit the energy coming up from the ground gets bigger and that gets a whole lot more energy sitting around in that part of the diagram and that's what we're worried about this part over here shows you what i was talking about earlier which is that most of what you see from space is reflected by clouds in our souls you know that seventy nine to twenty feet is plantation eucalyptus trees in australia the problem is that the amount of carbon dioxide we need to take out of the atmosphere is huge and the ability of plants to do so is relatively limited so really early on to reverse all that we would have to give up a lot of the farmland that has been taken vows we would also probably have to give up a lot of relatively low carbon biosystems we probably don't want to work anything like that we don't want to make planet work anything that hard there are other ways to get rid of carbon you can put into the soil there's more organic carbon about four times as much organic carbon in soils as there is actually in plants and again this is actually a nice thing to do for agriculture the very good reasons for putting more carbon into soils but again the actual size of the where the getting that much into that reservoir very hard to see how you would do so i billions of tons a year also the problem that if you do it and it doesn't quite work and you still get all of it's fundamentally limited and even if it worked much better than the experiments so far have shown and even if you are going to do it throughout the southern oceans still you're looking at about a billion tons of carbon a year and that's you know there's about ten billion tons of carbon being a method by humans at the moment so it's something but while you're sort of making carbon it's not necessarily something that you want to rush into especially since mostly you think of these interventions and you think let's try  minimize environmental change this start environmental changes the whole story ecosystem changes the whole story of your radically changing the ecosystem in huge parts of the planet now as it happens humans of already done this  rather more piecemeal way over the land part of the planet but the evidence is we made a lot of them we made a lot of mass while we were doing that we did a lot of good but we made a lot of math and we're not very good at governing the oceans at the moment which trees you're still talking about an area about the size of india to make of the dent in the problem through that sort of technology or you can use one of these the disadvantage of this piece of technology is that it doesn't  exist but this is a this is a hypothetical system for drawing carbon dioxide out of the atmosphere and then pumping it underground now i'm not entirely sure that something like this won't do this at some point but this would mean putting a probably will happen to some extent but it's not going to happen in the near future and there are other carbon dioxide mechanisms i haven't talked about the big worry is and we've mentioned the paris talk the power conference just before come close to meeting and it's not clear that any level of the missions or doctrine that anyone has ever discussed can actually meet that goal of keeping climate change well under two degrees and that's an interesting idea i think something like that's very plausible but it brings up one of the first of the three big problems with geo engineering that i want you to take home which is the problem is often called moral hazard this is a problem but if you think you can geo engineer you might do less of other things it's by analogy to the moment insurance or when people are insured they do things in a more risky way some things sometimes people feel safe are willing to take more risks people who think is going to come along and save them are willing to are going to do less in the meantime to decrease the risks by other means this is being discussed in principle in geo engineering circles some time in paris it became vet came home very strongly to me because you now have a world situation which the so i officially world narrative of what happens going forward is that we emit too much and then take back some of it later and it's very easy to see how that can turn into a meeting a bit more than that and i can back a bit dioxide out of the atmosphere it means we have to think about it harder we have to think about it realistically we have to think about the sort of processes that might work we have to think about the sort of cost we might be willing to to pay we've got to look at the sort of political processes and this is even more true for the second form of geoengineering want to talk about option to keep some sunlight out so that was the left part of kevin trenberth diagrams of it with the sunlight being reflected back into space you only need to reflect a very small fraction of the sun to increase of affection by a very small fraction in order to be able to do something about warming this is the thing that people probably most often discuss as climate engineering as climate geo engineering and they do so because it's considerably more dramatic and more scary than the carbon dioxide reduction versions of the story it's more and there are three ways in which that's the case  unlike carbon dioxide reduction it's not a simple reversal of what's going on it's in no way equal and opposite and so it goes in the it goes into a territory as well beyond the initial territory of just getting rid of a pollutant this is fighting climate change with a different sort of climate change which is not its opposite and will which will end up with a residual amount of climate change of  that's one thing another thing is it's prompt getting rid of carbon dioxide just like putting carbon dioxide into the atmosphere getting rid of carbon dioxide is a very slow burn sort of thing you'll notice that it's happening in tains twenty it a little bit brighter that could start having effect within months arm it could have an effect of cooling the planet noticeably in a couple of years and it could cool the planet noticeably could have a much bigger effect than any effect we talk about through carbon dioxide removal and that's not necessarily a good thing to have a bigger effect but it's a it's a representative of the third thing that's crucial about this form of geo engineering is its low effort they often said that it's low cost and that's a little bit more difficult because how you how you measure the cost of something is to some extent of moral choice but the fact is that in order to make the atmosphere  adding may be hundreds of thousands of tons millions of tons of particles of the atmosphere carbon dioxide were two talking hundreds of billions of tons taking out so you can see that you know there are many orders of magnitude particles reflected away some sunlight and the earth cooled it didn't cool very dramatically because by the time the cooling that started the particles were starting to fall out but it did mean that the next year the ninet ninety one was significantly cooler than it would otherwise have been that was an unfortunate the only thing that was different about it here is is that that effect in action that layers and those work all in the planet but they're also changing the way the climate worked they were changing the way that water moves through the climate system because that depends on the balance between direct sunlight and from the heat from the earth and they are also changing the chemistry of the stratosphere they were thinning the ozone layer in the most dramatic or the deepest ozone hole that there's ever been was just after pinatub so this is not something to be undertaken in any way lightly if you were to use this to fight climate change for instance by developing a fleet of new similar to you two aircraft and taking particles aloft in them you would probably be paying a fairly low cost at least to begin with been studies that suggest that can be done for between a few and a few tens of billions of dollars a year which is very very small when you compare it with the trillions of dollars a year spent on the energy system you might find the biggest problem was the problem that was where the political problems there are some studies some studies say that there will be strong winners and losers in situations like this some sort of say that if you do it in a very very delicate way there might only be winners in such situations but there would be people who won a little and people who won a lot and when there are people around who are winning a lot then winning a little can quite a lot like losing a bit and so this is  sort of thing where you can get international tensions and i think in general the risk factors with this sort of engine this sort of geo engineering are probably as as much geopolitical as geophysical  but they're real risk factors the fact that there are such risks is not to my mind a reason not to talk about such things and not even to research them it's a reason to try and research not just the pure physics of the matter but how it can be applied in the most useful something i should add there is just going back there are other ways to make the world brighter i mention this partly because of the people working on the my hair in the audience if you take this patch of cloud here and advair is of some other sort of sm particles to it you could make that a bit brighter cool the earth a bit more that patch of cloud up there too these are the sort of things of talked about as a marine cloud brightening and they are and so they have different spectrum of affect on the system to those of putting ourselves wired up at the top but they still have effect on the system and they possibly have bigger or certainly more focused political effects because they would have effect on on one region next to another region where there weren't such clouds to work with and there could be no effect so you might see different patterns of conflict with that sort of thing so moral hazard the big problem the actual risks both geophysical those who can't read it the man is on a stage rather like this say they say four hundred years ago a squirrel could go from the atlantic to the mississippi without touching the ground i dream of bringing back those days which is why i've developed develop the  about minimizing harm but i know that that's not the only reason people want to fix environments for people who want an environment that they can have a particular sort of a relationship with they want an environment that speaks to them about the relationship they wish to have with nature or with god or with their fellow people just getting the appearances isn't the point the point is actually to somehow be in a better balance than you are today  schools not touching the ground isn't the point the forest of the point and techno fixes are never going to speak to that sort of concern i think that doesn't mean that one should rule out technological  stuff but i realize that people have very different values very different systems of very different ways of thinking about the world this is one of the category mistakes one the the life ceiling leading to an ideological  problem the other one is related but possibly deeper on speaks back to promethea surround the beginning of the talk speaks to notions of tragedy tragedy as we know as we've been taught by the ultimate powers is another illustration of this is a picture curated by my friend michael light in some ways it's a classic version of a modern american of a twentieth century american landscape you can see the this this is a very lovely version of the western landscape the sparse foreground the mountains in the background the straight line of human intervention which i assume is probably a highway along there it's only when you look at it quite carefully that you which was one hundred fifty six and that ability of humans to mimic the powers of the sun is always something that should give us pause because of the way that it speaks to our history of technological development in the decades up to and after that when we talk about world changing technologies the nuclear weapons race and the continued presence of nuclear weapons clearly represents a sort of light high bar of the imagination because there's nothing more world changing than something that's world ending these are technologies that one should speak of in the same breath as geo engineering or to put encourage us to move forward with tat with trepidation yes of course it should do that but i don't want to end with with this particular bang and i don't want t sun and he created something called the weather project in which he wanted to get that sense of change in cycling and difference that i was talking about earlier as the essence of the planet and get it indoors and he felt in some respects the project was meant to have clouds in it and things like that and that never really paid off that was just so i kind of hazy not in some places but what he did get was the sun this is the weather project by  it was an extraordinary experience to witness it partly because all other people had been cowed by the size of the turbine hall he installed mirrors all along the top of it to create that sun floating in the air at the end of the building there was of course a huge historical technological arni about the whole thing that we were in a space that had been built to transfer the energy stored up in plants three hundred million you could actually pertained that it was the sun you could be moved by it like a sunset you could look i mean you can see some people down here people were affected with sunbathing there is no way of getting a tan of this object but there was a way of being together in a certain light that was attractive and moving and it brought people together in this strange way now i'm not saying that geoengineering is in some ways a huge piece of insulation  technology and that's wrong but you should also not be so foolish as to assume ex ante that you know that you can prejudge what the responses might be and here we saw and sorry i think i went on rather longer than i expected but we still have time for some question we yeah we have about fifteen minutes for questions just a reminder to come to mind the two mikes and keep your questions short so we can get to as many people as possible thanks you mention like the anxiety and i think that's a very important thing for people concerned with geoengineering more broadly to bear in mind people have already see the sky as a locus for various sorts of anxiety about technological change so i don't think there is any geo engineering going on at the moment of that sort but i am aware that there are people who believe so and i think that we need to bear with that in mind when thinking about how to discuss do you think you'd be safe if they did do as i discussed i mean i think in terms of direct the stratosphere became even appreciable even measurable of ground level y if you add on the extra climate change that you get that's mostly in the opposite direction from the sulfate all from any other form of our so then you will also get changes in patterns of rainfall and things like that you will  never almost never go to the models get a pattern of rainfall that is as that is as divergent from what we have today as as the pattern you know in a world of unconstrained climate change but the pattern changes so climate change tends to give more rain to people who already get global warming gives more rain to people ready get rain less rain to people who already are short of rain which is kind of kind of mean geoengineering would change those patterns and so there might be countries where the change was markedly different from what they would expect on the climate change and did not fit th agricultural practices or something like that and so you can conceive of how there could be losers in this and if you did it in a really big way if you did it sort of like like having a volcano go off every year there would undoubtedly be distributional facts like that that although the average temperature might stay very close to what it is today the pattern of change would be deleterious to some my feeling is about exactly the sort of area where you want to design your intervention in such a way as we try and meet that problem  from the gate but it's not always going to be possible so yes there could be distribution of problems that's why when did we have a loss and damage mechanism in the past agreement on climate because of course huge distributional problems in the climate change are already doing because the people who are doing the climate change are not the people who are suffering the biggest problems of the climate change water and so other than for the plankton right at the top there's an obvious possibility to move up in the up in the water column and that could very very easily overcome any effect and the other thing is this is a very small effect this is a sort of like though besides blanketing the earth blinking most of the united states with reuse or whatever it can you comment on the current state and feasibility of artificial carbon sequestration of the problems is that unlike plants which generate energy as they fix carbon dioxide those technologies need energy in order to fix carbon dioxide they are currently there are two companies which have moved to pilot project there's one in switzerland and one in canada they're both dealing in sorts of like a few tons to a few thousand tons not to a few thousand to two hundred billion tons and at the moment it's an extremely expensive approach and i think that what they think it's most likely to be used for in the medium term is probably either to enrich the atmosphere for growing for the for the near future but with you know one of the reasons that i harp on about my flight over here which was incidentally very pleasant was that you know no one talking about  travel in the early twentieth century or imagined that hundreds of millions in fact billions of people would routinely use aircraft to travel large ways around the world the degree to which there's something that actually the at one point which is that everyone always underestimate always overestimates technologies in the near term and underestimates them in the long term so i don't feel and in fact this is where i end up that chapter of the book i don't feel very able to say what people