And thank you all very much for coming to the 11th of our Gresham lectures on the environment, on the topic of net zero and in this lecture. So over this course, there's the fifth of the lectures this year. While we're talking about the, I mean, the overall theme is when net zero, so sort of how, how fast should we, we be thinking about stopping climate change. Um, and in, in the last couple of lectures, we talked about impact of climate change on extreme weather, and then in the most recent one, um, global tipping points and the kind of things that people typically worry about and ask me about in terms of how they, how they, uh, am I concerned about the impact of climate change on this, that, and the other. And, uh, uh, I, I just sort of start off by explaining this lecture is about what I really am concerned about. Um, and, uh, a long time ago, uh, mark Linus, uh, an author based in Oxford, somebody I've got to know quite well, um, published a book called Six Degrees. And it was all about the bad things that happened as you progressed up through the degrees as the world warmed. And I remember at the time, students asking me, I was on a panel with Mark, was I worried about Six Degrees? And the honest answer was not really. The Gresham College lecture that you're listening to right now is giving you knowledge and insight from one of the world's leading academic experts, making it takes a lot of time. But because we want to encourage a love of learning, we think it's well worth it. We never make you pay for lectures, although donations are needed. All we ask in return is this, send a link to this lecture to someone you think would benefit. And if you haven't already, click the follow or subscribe button from wherever you are listening right now. Now, let's get back to the lecture. Um, because, and not, because I don't think six degrees of warming would be really bad, um, but because I just think it's entirely moot, I don't think we'll get there. Uh, I think the, the, the, the things that worry me about climate change are, are not only the, the, the frictions that it's likely to induce in the world as we sort of, if we carry on as we're going and steam past two degrees, um, and also the potential destabilization of more panic stricken measures that might be taken to stop it. Um, and those are the two things I want to talk about, uh, today. So, um, both the risks of just allowing warming to continue the risks, the geopolitical risks of, um, measures like turning down the sun. So, um, so solar geoengineering, um, and finally probably more controversially for many people. I also think many people agree that solar geoengineering is a bad idea because of its potential impact on geopolitics. But I think we have to look at all climate policies through the same lens. We have to ask ourselves of all the measures people are proposing to take, uh, on climate change, which are the ones that, you know, are like, run the risk of actually destabilizing the world.'cause one of the things we've learned, if we not learned anything over the past few years, WW were rather better at killing each other than, than mother nature is. So, um, I think one of the things that I think we all need to think about is if it's true that, and I believe it is true, that, um, the, the risks, the geopolitical risks of some climate solutions may actually not be worth it. And I think solar geoengineering is one of them that's just not worth the risk. Um, then it, that the, the corollary of that must be that there must be some level of warming that it's actually worth settling for to avoid the potential conflict of eliminating it. And that's where people get, oh, really, you are sort of saying, but there must be a payoff. There must be a trade off there. Um, and, and I think we do need to think about that. And that's the sort of thing I want to, to talk about, um, in this lecture and in particular, sort of more precipitate scenarios for phasing out fossil fuels border on what you might call social geoengineering, which would be potentially very challenging and destabilizing, but for the world. And by the way, not just for the world. Um, I think we, we are entering a phase where in Britain, um, climate change is, you know, for whatever reason becoming an increasingly divisive issue. Um, and our people are pushing that. And, you know, that's, that's, um, the reform party on the line there, I'm sure. Um, and, uh, so, so, so, uh, we are facing the, the, the, the challenge of people of this becoming a much more divisive issue here as well. Um, so, you know, the overarching, uh, point of, of this lecture, the sort of three, three ways in which climate change could trigger, uh, a global conflict, uh, we have unmitigated impact, so we just let it go. And that I'll talk about that. We'll talk about solar geoengineering attempting to control the weather, and we'll talk about poor mitigated the potential side effects of poor mitigation policies. Um, that's probably the most controversial question. So as far as you know, the, the geopolitical consequences of just letting the world warm, um, I thought I'd start from this, um, very, um, well-known diagram from the intergovernmental panel on climate change, this is the way they represent the risks of different levels of warming, and by and large warming, does the, the physical risks of climate change do scale with the amount of warming we've got? And the transition here from sort of yellow to red is from, uh, uh, moderate risk to high risk and so on. And you can see by the way, that, that this is, that the narrow, um, columns are from, uh, are the, the fifth assessment report that was back in 2014. The broader columns are from the latest assessment. And you'll notice that one of the shifts in the climate community and research community has been to, to, to bring forward the point at which we think there's higher risks to the various reasons of concern that the IPCC has identified. Um, people do often ask me, is it worse than we thought? And the answer at the sort of global level, at the kind of modeling the overall climate response to rising greenhouse gases, the kind of thing that I do, um, the answer is not really, it's sort of evolving pretty much exactly as we expected. But when it comes to the impacts of the warming we're seeing, we're tending to see these impacts appearing earlier. And, and, you know, e each successive revision of the intergovernmental panel on climate change reports has tended to bring forward the points at which they're saying there's, uh, high risks to different systems. And they classify this in these various ways. And so, um, you'll notice there's, there's five reasons con concern. They talk about unique and threatened systems. That's, um, the Arctic ecosystems, uh, like, or, or coral reefs, ecosystems that are particularly, uh, impacted by climate change. Um, extreme weather, we know what that is. Um, uh, distribution of impacts, we'll come back to that. Global aggregate impacts are, when we're talking about, say, the impact on the entire world economy, sort of what's the overall aggregate impact of climate change on the world economy. Um, and large scale singular events are sort of things we were talking about in the last lecture, um, shutdown of the Thermo hairline, circulation collapse of the West Antarctic ice sheet, that sort of thing. So I'm generally speaking, um, if you sort of ask what people think they're concerned about, um, in climate change, it's, you know, the unique and threatened systems, you know, dying polar bears. Um, if you, um, speak out, well, you can produce postcards that you can send to your friends to get them worried about climate change. And these are the sort of things, but I thought it was interesting. The, the topics they've picked out, hashtag speak out has picked out. Um, and, uh, uh, you know, they picked out, uh, obviously threats to the arctic threats to low-lying, uh, nations, the Maldives, I believe this is, um, extreme weather, wildfire risk there, large scale singular events like collapse of ice sheets, um, more extreme weather. It's sort of, those are the three people focus on. And of course, economists are worried about the aggregate impacts on the world economy, but the reason we concern that I think we are actually most concerned about is not, is rather mysterious number three, distribution of impacts. And what it means, what it, what it's defined as in the IPCC report is the risks and impacts that disproportionately affect particular groups due to uneven distribution of physical climate change, hazards, exposure or vulnerability. And this is the one I'm most concerned about, because back to the theme of this nature, it's the one that has the most potential to impact on geopolitics. But to explain why I think other people are most concerned about it too, whatever they might say, and whatever the, whatever postcards they might send each other, um, I think this is the one which ultimately gets people, you know, gets people, uh, anxious about climate change, is these, these, uh, emerging injustices, uh, in the climate signal we're seeing already. And the reason I think this, I can sort of sum it up, um, with, with, um, actually sort of three things. Uh, John rules a, uh, American philosopher, um, disaster movies and the People's Postcode Lottery. So these things are linked. Um, John Rules, um, was, uh, an American philosopher, um, who, uh, in the early seventies produced a theory of justice, which was based on the premise that you had to imagine organizing a, a just society was one in which you would deem it as just even if you didn't know who you were going to be in that society. So he introduced the idea of a veil of ignorance that you didn't know who you were gonna be. So how would you want society to be organized without knowing which member of that society you were going to become? That was the sort of thought experience, and it has various consequences of this. And one of the key consequences was the, it it, it highlights and it works because, as a philosophy, because I mean, people liked it, people adopted it, and a lot of people cited. And, um, one of the consequences of John, of Ian philosophy is a strong aversion to individuals losing out, specifically losing out relative to their neighbors. No, nobody would, no, nobody likes that prospect of, of maybe being suddenly much worse off than your neighbor. And which is, I think it's the, I think it relates to the way we react to disaster movies is that the, the, the, the, the, the disaster that occurs in a disaster movie occurs to everybody, and people find this almost strangely reassuring. Uh, yeah, it's the end of the world, but you know, every, you know, it happens to everybody. I think, what was the, the one exception to this, by the way, which was a very, very clever movie, don't Look up, uh, of course, the, they kept the, they kept the, the, the ironies going all the way through that movie, and they had all the hyper rich people went off in a spacecraft frozen at the end. Sorry, I'm, I'm spoiling this spoiler alert here. But you know, they, they, they kept up the fact that there were, the unfairness continued, you know, even all the way through to the end of the movie. Um, why do I think the People's Postcode Lottery isn't, well, I get exercised by this kind of thing because, um, so it is not that relevant, but I do, it does make me very angry. So the People's Postcode lottery, I dunno if you, if you, uh, if you follow this sort of thing, but it's designed that if, if, so here's lots of happy people in Altham, um, who've all won, you know, 10 grand each because they played the People's Postcode Lottery. Um, what it doesn't show you is the other people of Altham whose neighbors are all annoyingly smug, okay? So the way the people, it's, it's, it's, they're actually exploiting rules and philosophy. They may not say this on their website, but what they're doing is they're frightening people into thinking you are gonna be worse off than your neighbors if you don't buy a people's postcode lottery ticket. It's, it's blackmail of the poor at the lowest level. And I cannot understand why it hasn't been banned. Anyway, um, the problem is with, with climate change, with, with what's happening is it's, it's emerge already. We're seeing very uneven, even at relatively modest levels of warming, you know, up to two degrees, we're seeing very uneven impacts of climate change on countries around the world. And, uh, we did some work in the buildup to the, uh, IPCC 1.5 degrees report, looking at the economic impact of, um, one and a half and two degrees of warming relative to where we're, where we were at, which is one degree of warming today. And, you know, um, the, this was, this is work actually, which, uh, Felix Preis led in the, uh, economics department in, in Oxford. What what I found was really interesting about this work was it was entirely empirical. He used empirical relationships between productivity and temperature, um, in, in different countries around the world. He managed to show that a very clear, geographically distinct pattern. You know, hot countries lose out, cold countries do well, um, out of the climate change. And by and large, if you also look at, uh, you know, so you can see that, that there's, it's, it's primarily countries in the deep tropics, which typically also countries, um, that have not contributed a huge amount per head of population to climate change. They're the ones who are most impacted by climate change to date. Um, and of course, um, if we, you know, go and look at the individual countries, you know, at the top of the list you've got, you know, Finland, Russia and so on, doing relatively well out of modest levels of warming. And at the other end of the list, you've got, you know, um, Maia, Mali and so on down at the bottom. Interesting. You can see United a Arab Emirates there. That's of course, because this is looking at the impacts of the warming, um, on, on these countries, not the impacts of, not the economic benefits of the things that cause the warming. So you may be slightly surprised to see the United Arab Arab Emirates there, but you can sort of see, see why. And of course, because we've got these very uneven impacts of warming that is compounded by the fact that we have equally uneven, even more uneven contributions to warming. Um, and the fact that the richest 1%, uh, of the world's population is responsible for, um, the same emissions as in, in, in, in, in consumption terms, is responsible for the same emissions as more than half the world's population. Um, so that sort of extraordinary unevenness of both the causes of climate change and the impacts of climate change is something that one, one fears, if we just carry on as we are, is gonna fuel evermore resentment and instability. And in fact, when you, you know, the, the, the, the, the, the conversations at cops, um, are, are in fact, I find remarkably civilized when you think about what's going on and what, and what is, you know, what the negotiations are over, um, have, it's, it's, it's actually, it's often quite a, a amazing how, how polite and, um, uh, yeah, as I say civilized that the developing countries who are really being badly impacted by climate change are, which is why, of course, I find this sort of mantra of many energy companies, uh, since, since the last lecture, by the way, I had an interesting experience of going to SRA week. You probably haven't heard of this. I'm sure you've all heard of cops, but what you probably didn't know is four months after Cop, there's an anti-cop, which happens in Houston, of course. Um, and the fossil fuel industry gathers together and, you know, basically decides where to drill next and that sort of thing. Um, and, uh, they like to invite academics along to talk to them, but they, there's a lot of this sort of stuff was being talked about, oh yeah, we have to keep drilling, we have to keep producing because, you know, otherwise the world's poor will, will, uh, miss out on, on our, on, on, on, on the, the wonders, uh, of fossil fuels. And of course, you really, I mean, the people benefiting from continuous of fossil fuels are by and large not the world's poor. Um, so, um, and of course, in, in closer to home, uh, this is a, a very common mantra of, uh, outfits like net zero watch the, um, group that's, uh, sort of taken over from the, um, global warming policy foundation. And they're always sort of full of how green taxes and so on are gonna hurt some, the, the, the poor. Um, and yeah, of course you need to be careful that, um, climate measures don't hurt the poor, and it's something which we and in Britain, I think need to put a lot more attention to. Um, but, uh, uh, the, the solution to that is obviously not, not to have any climate. Well, their solution is, so you don't have any climate policies. I mean, no, you can design your climate policies so that they don't adversely affect, um, the poor. Um, and you know, if you just decide, you know, if you listen to net zero watch and decide, well, it's just not worth having any climate policies 'cause they might adversely affect the poor. Um, you end up, you know, with essentially climate inaction, uh, which even, you know, hard hardheaded, uh, folks like the, uh, US National Intelligence Assessment, um, you know, have, uh, consider that, that, that, you know, this is actually one of the highest risks they, they see to US securities. So these are, these are sort of military planners taking it, um, very seriously. And it's interesting that the, the perception of insufficient contributions to emission reductions is at the top of their list of geopolitical risks in this report. So it's the idea that all those red countries in that map who are most adversely affected by climate change and by and large, have the population which is down at the bottom of that, um, shaped, uh, uh, that, um, uh, uh, uh, uh, will sort of increasingly become increasingly resentful of the countries that are doing well outta climate change. So it's, this is absolutely not, so worrying about geopolitics is absolutely not a reason for climate action, climate inaction. Um, but at the same time, we have to worry about certain kinds of climate action. Um, and the one I now want to talk about, um, for, for, uh, the next part of this lecture is this idea of intervening explicitly in the climate to effectively turn down the sun, um, in order to cool the planet. This is an idea which is, is out there, it's being discussed, it's being discussed more and more actually. And, um, the UK government has even, um, sort of seems over the past year or so to have sort of changed its mind and decided to actually start funding some research in this space. Um, it's gone back a long way. Weather control was big in the fifties. Um, I love the fact that back in the 1950s, you always put a tie on before you destroyed the world, you know, it's like <laugh>. Um, but anyway, so let's just go through sort of these, um, uh, the ideas that are out there. Um, one option is to enhance the reflectivity of the surface. Um, and this is, uh, uh, there is actually a research group in Cambridge, um, that has got funding to go and, um, pump water onto the surface of sea ice in order to have that water freeze and enhance the reflectivity. And there's, so they're actually aiming to intervene, um, to try and refreeze the Arctic. Um, yeah, okay. Not, not, not, uh, not a research group I'm a member of. There we are. But, um, uh, anyway, an interest. It's, you know, we, we, we do have active active research programs in this space. Um, a another, uh, another, um, uh, idea is, um, to increase the brightness of low clouds, um, over the oceans, again, to reflect away more sunlight. Um, that's one of the interventions that we kind of incidentally have quite a lot of in, in information on already, which we'll come back to in a minute. Um, number three, um, increasing the, um, reflectivity of the stratosphere by putting material into the stratosphere to reflect away sunlight. This is the sort of synthetic volcano idea. Um, finally we get onto the more sort of, um, uh, well gonna say farfetched or at least certainly expensive options like space-based, um, uh, mirrors or sunshades. Um, and, um, deliberately decreasing the amount of high altitude sru. Um, so, um, you are, you are all familiar with contraras and the arguments that contraras may be contributing to global warming. Um, but there is an argument that you could actually try and go, go sort of into a sort of anticon trail. You could actually try and intervene to try and get rid of natural sru in order to try and reduce its warming effect. Um, all of these ideas are out there. They've been out there for some time. We quite often see artists' impressions like this one. Um, can anybody spot what's wrong? Uh, fortunately it's an artist's impression, or some engineers would've got That's right, yeah, the sun's over there, guys, you know, so, okay, so, so whoever put that mirror up, uh, didn't, didn't really do anything anyway. Um, but, uh, but more seriously, um, there are options out there which we know would work. Um, and the reason we know they work is 'cause we, we, we have sort of accidental experiments going on. So this is a picture of the Pacific, um, cloud cover over the Pacific. And if you look carefully, particularly if you use a machine learning algorithm to, to, to spot them for you, you can spot all these tracks in the clouds, okay? You see them. The, the purple is just highlighting the ship tracks. And these are, are, uh, the, the additional cloud that's generated as a result of the pollution that's coming outta the, um, smoke stacks of, of, uh, the, the engine exhausts, uh, of ships. And, um, we are actually performing an experiment at the moment because just a couple of years ago, we introduced new low sulfur standards for marine bunker fuel. So the, um, uh, and we also had an interesting experiment where we had a global pandemic, and that also reduced shipping quite a lot. Um, but we're seeing, so the global pandemic was fortunately only temporary, but we, the, the marine bunker fuel rules are persisting. And so we're actually able to see the impact of a reduction in the pollution in, in marine pollution on low cloud. So we're actually seeing, um, some, uh, impact already, um, of the, and, and, and in fact, I was just hearing last week, um, I think it's still under review this paper, but colleagues, uh, uh, in, in the us, um, have actually been think they can detect even a, a, a, a consequence of this in the temperature record that they're actually sort of seeing a little bit of, we've seen a couple of, as you, as you all know, this past year has been a very warm one. And maybe some of that warming, I wouldn't push the boat out as to how much, but a little bit of what that warming may have been contributed by the fact that we've cleaned up, um, ship tracks. That's a good thing. It was bad pollution over the ocean coming from this high sulfur fuel. Um, but as a result, um, we've, we've, uh, uh, we've reduced the amount of low, uh, bright low cloud, um, in the, uh, bright low cloud in, in o over the oceans, which has the result of, of actually raising global temperatures. So obviously the obvious implication is, well, wait a minute, maybe we could just put the sulfur back or maybe put something back into the marine fuel that's that's not quite as nasty as sulfur, um, and, uh, brighten up those clouds again. So, you know, yes, you could do that. I mean, this is, this is the point here is that, you know, we do know that this kind of intervention is possible, and therefore, you know, solar geoengineering could, if you implemented it, it could actually have an impact on peak warming. And this is the kind of scenario that people like to talk about, uh, where you've got warming heading up. Um, here's, this is a, one of the figures from the 1.5 degrees report, um, and, uh, sort of imagine a scenario in which temperatures are heading towards 1.5 degrees, and that pink line is 1.5 degrees line there. Um, you are, you are reducing emissions. You can't reduce them fast enough. So you, you, you realize you're going over 1.5 degrees, you deploy, um, a sort of geoengineering scenario. You pump lots of, um, this, the scenario here is the, the stratospheric injection one, you, you pump lots of material into the stratosphere, um, and you reduce the incoming, uh, radiation by, you know, just the amount, just the right amount, um, to sort of shave the peak off the global temperatures. And this is, this is sort of suggested as a good, good, good thing to do. And it's even actually, we've even gotta the stage where people are saying, well, this is, you know, possible and cheap, and you can even do it right away. You can buy a, a bit of solar geo engine. This is a company, uh, make sunsets that is releasing balloons into the stratosphere above America. Um, and, uh, yeah, the balloons, uh, sail up into the sky. Here's, they, they, they're clever. They put cameras on them so you can sort of see what your, your balloon is doing. Um, that's the view from the balloon down over, I think it's California. They, uh, it must be California actually.'cause they tried to do this in Mexico and Mexico apparently banned it. Um, but, uh, um, and this is the view of the balloon, and then you see it bursts and that puff this, that sort of gray cloud, you see you're falling away after it bursts. Um, and that, that, um, that that sort of slightly murky yellowish cloud, that sulfur dioxide that's been included in this balloon. So that's now going out in the stratosphere and the saying, well, that sulfate oxide will form a, uh, sulfate aerosol is the argument there.'cause when you, when you put that sort of gas into the stratosphere, that's what happens. Um, and, uh, uh, they, this is gonna cause some, some cooling. So they're saying, um, for, for, you can go to their website and you can for, for nine quid, you can offset the warming effect of one ton of carbon dioxide for one year. And then underneath this, they say, offsets one ton of carbon dioxide for one year. The average American generates 15 tons of carbon dioxide per year. If you've really been concentrating in these lectures, why is this misleading advertising? So can the average American, you know, what you are clearly meant to do is multiply that by that and think, you know, I can offset my carbon dioxide emissions for a mere 135 pounds a year. Um, anybody wanna comment on what's wrong with this logic? Mm-Hmm. So, so Only The one year, it's only the one year. And how long does the carbon, how long does the temperature impact of your carbon dioxide emissions last forever? Yeah, okay. So in fact, what it actually takes to neutralize the carbon dioxide. So suppose you were emitting 15 tons a carbon dioxide per year, you know, you need 1 35 pounds in year 1, 2 70 in year two, you know, and so on, you know, 12,000 pounds in year 90. And, you know, okay, at some point you're gonna stop emitting, but then it's like forever. Yeah, that's the problem. That's a fundamental problem with this sort of approach. If you're gonna try and compensate for the impact of, um, of carbon dioxide emissions by dumping stuff in the stratosphere, you're taking it, you're making an absolutely permanent commitment to keep doing it until you've actually taken the carbon dioxide back outta the atmosphere again. Which of course is what happens in that scenario. I'll just go back to em. Oh, we'll, we'll come back onto in it. But, um, to be fair, I mean, I, you know, I think, um, makes sunsets are, are, if you go further down their websites, you can get a big discount if you take out a monthly subscription. So maybe that sort of makes the, makes the, the economics a bit better. But the point is, you know, seriously though, uh, um, you know, particularly if, if it was done on by a government or something as a sort of big, big scale program, cost is actually not the main issue with, with sub general. It, it would be, it would be affordable if somebody was to decide to do it. But the, the reason, the, the real issue with it, and the reason it's so destabilizing is because of course, there's more to climate than just global average temperature. And this is an excuse for me to talk a little bit about climate physics again, um, and, and tell you, tell you why. Um, so reflecting away sunlight, um, it can have an, a sort of equal and opposite effect on global temperature as increasing greenhouse gases. But it can't have an equal and opposite effect on the climate as a whole, because of course, the climate as a whole is much more than just the global average temperature. So there's certain, there are absolutely certain to be side effects of a program where you are modifying the climate by pumping material into the stratosphere to, to, to hold down, uh, surface temperatures. And that's when the arguments begin. And let me just sort of illustrate one of these side effects with this, um, uh, animation of this is global precipitation. This is precipitation around the world. And, uh, from NASA's, I merge, uh, satellite dataset. And, and what are you, you should find sort of impressive about this? Uh, well just drawing your attention to about, about this, um, uh, uh, uh, this dataset is that, you know, you can see the journal cycle, the daily cycle of temperature and the tropics and so on. You can see how noisy it is and how apparently random it is. But if you sort of fuzzy your eyes a bit, you'll notice the total amount of precipitation doesn't really change very much despite the fact that in any particular location, it's changing massively. So what's going on? And in fact, if we look over time from 1980 to mid 20, um, mid 2010s, you can see global average precipitation in this lower figure, um, barely varied by, you know, more than plus or, you know, plus or minus 2% very flat at the same time, the global average temperature was actually going up quite a lot. And, you know, global average temperature went up by about half a degree over that period, precipitation, flatlined, and, and, and not only flatlined, but it didn't even, didn't even wander about it seems to be sort of kept at a particular level. And, um, it's, it's really interesting why, um, what, why it is that precipitation, global precipitation is, is kept so constant. And, and the answer is, it's an interesting piece of physics, um, in that when, when a cloud forms and rain forms in the cloud and rains out, it releases energy into the troposphere, into the upper troposphere and warms it up. So, so, um, if you, uh, you, you probably, you, you all know that air gets colder with height, but when a thunderstorm occurs and you have rain, air gets less cold with height. So lemme get this right. So colder, colder, warm. I'm trying to get that. So you, a thunderstorm occurs and it, it's, it's the temperature is, is is pushed up, um, in the str in, in the upper troposphere. And then of course, because it's, um, falling off less rapidly with height, the atmosphere is stabler because there's, there's the, the, you've got warmer air over colder air, and that suppresses convection again until the air in the upper troposphere has cooled down again. So it's, it's, it's, it's warmed up by the convection and then it gradually cools down, and then it, then you get the, the next event goes off. So like many processes, um, rainfall, the overall, what we call the global hydrological cycle is controlled. The rate of rainfall is controlled by the slowest step in this sequence. That's, chemical reactions are like this as well. It's always the slowest step in a reaction that determines how fast the whole reaction takes place. And the form, the form, the formation of a cloud, the formation of rain, and so on. That's all very quick. But this cooling off of the, of the atmosphere after the rain has formed, that's what takes time. And that's what determines the, the, the, the total amount of rainfall that happens in the world is the ability of the atmosphere to get rid of the energy that's being released by the rainfall. And we understand this, this is, this is the basic sort of physics of how rainfall is controlled. And that's why you saw that very, that's why we see a very constant, um, uh, uh, amount of rain here and why you saw that sort of very constant rainfall around the world in, in the, in, in the animation. Um, but then you, you, you be, again, you might be puzzled because you think, well, global temperature's going up and a warmer atmosphere should be able to get rid of energy faster because it's warmer, it's been radiating more, and therefore, why are we not seeing more rain? Well, um, the answer lies in what's driving the warming, of course, because if we increase, um, and this is a figure from a kind of very old paper, but the, the point still stands, um, that shows the warming in lots of different climate models resulting from an increase in carbon dioxide doubling in this particular case against the precipitation change in the vertical. And you'll notice they, they fall on more or less a straight line, but it doesn't go through the origin. So if you were, if you were to double carbon dioxide in a climate model, and we do see this in climate models, when when you do this, you actually immediately reduce the ability of the atmosphere to get rid of the energy released by rainfall. Yeah. Because you are making it more opaque. So it can't, it can't get rid of that energy as, as efficiently remembering those, those of you at last year's lectures can remember those pretty colored balls, which I told you about, how, how the atmosphere got rid of its energy. And then of course, it warms up and you go off in this direction, and that's the temperature dependent effect. But if you were to compensate for the temperature dependent effect, come back down this red line, you don't get back to where you started. You get, you know, you've got all that sea, all that carbon dioxide, which has dried out the planet. So if you were to compensate for the temperature dependent effect by, um, pumping, uh, material into the stratosphere, you sort of artificial volcano idea, you end up down here. So you swapped global warming for global drying, and you can't get around this, you know, this, this red line does not go through zero, so there's no way back to zero. And at a regional level, it's even more obvious. And this is a piece of work, um, done. But we had a, a visiting student, Kate Ricky, who's gone on to actually become one of the, uh, world's leading experts in solar geoengineering. Um, and she, um, in a, in a really nice study showed how the regional impacts of geoengineering were different over India and China. We just chose those as two, um, big blocks of land. Um, but also because of course, um, well, they're, they're, they're powerful players. Um, and if you look, uh, just focus on the 2070s results, um, this is a, a, a scenario in which there's a discussion about how much geoengineering do we want. And the circle shows pre-industrial climate, sort of within one standard era of pre-industrial temperature and pre-industrial precipitation in these individual regions. And you'll notice that, you know, um, if we go for more geoengineering, China's happy, they're back inside the circle. But India's outta the circle, India's been driven to a, a climate that's, that's different from its pre-industrial. And of course, if you go for less geoengineering, um, then India's happy they're inside the circle, but China's not. So this kind of regional disparities are inevitable from a geoengineering. And you know, I've, it's taken me 10 minutes to explain to you why, but everybody can understand this. And so, I mean, the governments of Indian China may be very rational and they may be able to sort it out and, and, and, and, and agree on that, but you know, there are others. Um, here we are, thanks to John Berman for pointing this out. Um, this is James Delling poll. Anyone who still believes that the weather is not being deliberately engineered to create food sausages deserves all the food price inflation and starvation we will inevitably get. Now, nevermind James Delling poll is saying this, but you know, 135,000 people are, are, are, are reading it, lots of them are liking it. Um, even with what we're doing today, I I always find it intriguing how the conspiracy theorists are convinced the government's very incompetent, but then they're convinced the government's doing something really clever <laugh>. I mean, how, anyway, nevermind. Um, but some, but the point is, you know, it, it, it, what, there's enough justification if the government were actually doing this, you can imagine the conspiracy theorists would be having a field day. Um, so, um, you know, as I say, effective geos, geoengineering, which actually sort of does enough to make a difference, is unique destabilizing, unlike removing carbon dioxide from the atmosphere, which does have a sort of compensating effect, putting carbon dioxide into the atmosphere. Um, solar geo engineering can only be done on a global scale. There's only sort of one, there's only one climate view to intervene in, and it can't compensate fully for the impact of the carbonide emissions. So, by the way, I think one thing, one thing I do feel very strongly about is that reports like this one, again, it's, it's a long time ago now, but it rather set off the way of thinking. Um, for 10 years people thought of carbon dioxide removal and solar radiation modification as sort of two parts of the same thing. They're not, they're fundamentally different. One is actually compensating for the impact of putting CO2 into the atmosphere. The other one is this sort of, um, sticking plaster. Um, and when we come back to this scenario, if you look at the sort of this, this was included in the 1.5 degrees report as a sort of suggestion of a, how solar geoengineering could be relatively harmless. Um, but if you look at what harmless implies, you realize that you are actually deploying the solar geoengineering after you've already reduced emissions by, you know, almost half, and you're well on, you are only a couple of decades off net zero. Why on earth would you at that point suddenly head off on a complete tangent and start deploying geoengineering? Um, and of course, when the impact of the geoengineering is actually sort of, kind of within the uncertainty in the response anyway. So fortunately for now, there is a global moratorium, moratorium in place. Um, back in 2010, uh, in the convention on biodiversity, um, they agreed that they, there there would be, um, the governments would ensure that no climate related geoengineering activities that may affect the biodiversity, which means them all, um, may take place until, you know, there is a sort of get out there until there's an adequate scientific basis on which to justify such actions and appropriate consideration of the associated risks. So it's, it's a moratorium for now. Um, and you know, so I, but most people agree that it's the, you know, solar geoengineering could work. There's no sort of really, there's no really argument over that, but it's that, it's the, um, it's the geopolitical, um, implications of of solar geoengineering that really, really frighten people. And I think, um, deserve to be deserved when, um, uh, when people are sort of talking about deployment, there's often, or talking about sort of research programs in this, they say, well, you know, don't worry. We'll have a un committee that'll manage it, or, you know, and really, um, we, we don't really do that sort of thing very well. Anyway, um, to get onto, just to, to, to wrap up, you know, I think to be fair, you know, I've, I've, I think solar geoengineering is a particularly destabilizing measure, but I think to be fair, many climate policies have the potential to be destabilizing. And we do need to think about this.'cause I say, as I say, I think we do need to think about, you know, the trade offs between we need to stop the warming as soon as, you know, we keep hearing we need to stop the warming as soon as possible. Is that quite correct? You know, is is do, are there measures that would actually be, um, uh, would, would, would, would, would be so destabilizing, um, that, that, you know, it might even be worth accepting a couple of tenths of a degree more warming to avoid having to take those measures. I think solar geoengineering definitely fits into that category. Um, but there may be other ones as well. And, you know, I think we need, do need to think about the implications of over precipitous, um, emission reductions in that category as well, what you might call the social geoengineering that would be required to achieve some of the more ambitious, um, demand reduction scenarios that people are very fond of pointing to as the way they'd like us to solve climate change. I mean, at COP 28, we had lots of people enthusiastically saying, you know, we've gotta phase out fossil fuels, um, as fast as possible. Um, and, uh, um, but not, I think recognizing that trying to achieve our climate goals by phasing out fossil fuels means phasing them out completely in the next 20 or 30 years. And that in itself carries risks if we look at these scenarios. So this is four scenarios, all of which achieve 1.5 degrees. And what I'm showing you here is energy use, not emissions, but energy use in these scenarios from different sources. The, the dark green is fossil, conventional, fossil, um, conventional fossil fuel, uh, energy generation. And so you can see in two of these scenarios, we effectively phase out conventional fossil energy generation. The other two, we reduce it, but it doesn't get phased out entirely. So what does it, what does that entail, that sort of fossil phase out scenario? Well, in one class of these scenarios, it means an immediate, that means this decade, 30% reduction in final energy demand per head of population. So I mean, no, no government has any appetite whatsoever for that sort of, and, and, you know, whenever governments have tried to reduce demand like that, the result has been pretty explosive. Um, I mean, remember Macron back in, uh, 2018, for example, um, and then the, the other category actually involved, um, amazing amounts of bioenergy production in the second half of this century, which, uh, we, we, we've perhaps come into. So this is what worries me with some climate policies. It makes it a bit sort of too easy, um, to come up with this kind of thing. And, you know, okay, I hope, I'm hoping, uh, this particular demonstrator a minority. Um, but, um, you know, the fact that that's out there, um, and that it's increasingly entering the UK political discussion, I think is, is worrying. Um, and, and I think the, um, proponents of climate action of which I'm, I, I absolutely one I think need to look at what we're advocating for and, and, and, and way up, you know, what are the implications of climate policies on different political pe people of different political persuasions and people in different social groups in order to make sure that we prioritize inclusive climate policies that don't divide people. I think at the moment, actually, particularly in the run up to this election, you're gonna see, I think, you know, both sides seem to be quite keen on making climate an, uh, an issue in the election, um, in a pretty unhelpful way. Um, because, you know, if the conservatives are seeing it as a, you know, climate's just this woke issue for the urban classes, that's, you know, okay, that's, that's, that could really contaminate the conversation about it for, for decades. Um, but I think, you know, we need to look at the kind of policies that labor's putting forward as well. Um, and, and ask yourself, you know, are they really designing them with inclusion in mind? Um, you know, one, one particular policy that we'll, we'll be talking about in, in, in the next, um, in, in the next lecture and, and indeed next year, um, the idea that you, um, ban new extraction of fossil fuels, um, that's, um, it, you know, it doesn't, it doesn't have an obvious impact on emissions. It makes it very easy to sort of polarize the debate around it. Um, and it makes it, you know, very much on those communities that are immediately affected by a fossil fuel extraction ban. Um, it's a way of dividing people up, and it doesn't, it seems to me an unnecessarily divisive for, for its minimal impact on the actual problem. It seems to be an unnecessarily divisive policy. Plenty of people disagree with me on this. I should, sorry, I should stress. Anyway. So to sum up, um, you know, I worry about, overwhelmingly about the geopolitical risks of climate change. I think it's, it's the impact of climate change on us and the way we interact with each other that are the biggest risks that, that, uh, in this. And one of them, um, one option of just sort of not doing anything because you're worried about the geopolitical consequences or the political consequences, um, that will eventually just stoke resentment. Um, probably not just eventually it's already stoking resentment. Um, so, so, you know, this doesn't, this is absolutely not an argument for non policy on climate because you're worried about offending people. Um, quick fixes, particularly solar geoengineering is likely even worse in terms of stoking, um, perception, perceived injustices and perceived anger about this issue. But we have to apply the same lens to all policies. We have to ask ourselves, you know, you know, when particularly draconian policies, which would be required if you wanted to try and address climate change, pri focusing heavily on de demand, um, which is the way a lot of the climate mitigation policy community are going at the moment. They're saying, well, you know, the technologies aren't being deployed fast enough. The only option left is to really focus on demand and reduce the amount of consumption around the world that's has the potential to become really, really divisive. And, and I think we need to ask ourselves, you know, are these, are these, um, rapid demand reduction scenarios worth, worth, the likely, um, social impact, social and political impacts, uh, that they may have? And, uh, the conversation will continue and we'll come back to it. But anyway, so that the, that's, uh, uh, that's sums up this one. But in the, in the next, on a much more positive note, so sorry if this has been a rather sort of negative and gloom gloomy, uh, lecture. Um, but in, in, in the final lecture of this series, we will try and talk about sort of what can be done, what on the positive side, what can be done to design inclusive climate policies to avoid these kind of geopolitical tensions? Thank you. First, uh, perhaps the, the question of, um, you said that there is the lack of, um, consensus among, among countries, and, and there is the question about actually the potential implication of unilateral deployment, of, of solar engineering, uh, techniques. What could be the, the, the potential implications of that? Well, I mean, it's already happening. I mean, those guys in California are letting off these balloons. I mean, I, I, I, unfortunately, they're only letting off a few, and I, I think assume, I assume once they get to any scale, they'll just get banned and that'll be the end of that. Um, but they've made plenty of money. I mean, they've got, if you look at their website, they've, they've got lots of investors piling in and, you know, so, so, um, so you clever guys in the short term, I'm not sure it's very good for, um, but, but yeah, I mean, the point is that even a private, even a wealthy private individual could start messing around with, with, with the earth's climate. Um, the, the difficulty of course is you can't do it secretly. Um, so it would be very, it would be pretty much impossible to, to start geoengineering without people knowing that you were doing it. And as a result, you know, the conspiracy theists, but even non conspiracy imp perfectly sensible, people would immediately start to say, well, wait a minute, they're doing this program and I've just got this mega drought, which is killing all my relatives and so on. You know, maybe this is related and you'd have some justification for that. And, and that's the problem. And that's when the, that's when the potentially the wars start. And interestingly, are they actually computing the carbon footprint to create, to make the balloons? Because this has<laugh>, I'm, I, I wouldn't wanna start getting into those sort of arguments. Maybe they have, but I mean, you know, or Even just other forms of solar Engineering Techniques, that's quite an Interesting, no, but there is no question that, that that stratosphere, stratospheric aerosol injection or, or marine cloud brightening for that matter could be done, it would be relatively cheap. I mean, that's the, you know, that's the sort of scary part of it, is it, you know, it's affordable. Um, but it definitely has side effects and it has comprehensible side effects. It has side effects that everybody would understand, and therefore everybody would, you know, feel if they, if they feel they, if every, if, you know, if people, it's, IM, it's impossible for a government to get away with saying we're doing this, but don't worry, it's not having any adverse impacts anywhere in the world. Um, you know, because somebody would blame them for the weather. Um, another question is actually related is about, well, to avoid conflict, it seems that transparency and accountability is, is, is key here, and, um, it has to be insured. How, how can we make sure of this in the sense that there is a lack of awareness of all these, uh, techniques and and so on? I mean, I, yeah, I, I I, I know that this is, I mean the, the, uh, there's a foundation, um, I'm blanking on the name Yash pastor is, is is the head of it, um, uh, where they talk a lot about this sort of accountability and inclusion of different countries and different perspectives and so on in discussions about geoengineering. I think that's hopeless, to be honest. It doesn't matter how transparent you are, you're still gonna get blamed. In fact, arguably the more transparent you are, the the more you're gonna get blamed for, for, for the weather, regardless of whether it's true or not. I mean, we, you know, you saw the, you saw the tweet, I mean, it, it, it, it, it's, and there's, there's enough of a reasonable narrative there for there to be that risk. And, you know, inevitably if this actually happens on any scale, it will be with the blessing of the big military powers. So, I mean, for this to be done on any scale, basically, it's either done by the US or China, or done by somebody else with the blessing of the US or China and, and probably both. I mean, you'd need, you know, and, and so therefore the US or China or both would be held responsible by the rest of the world for this program that they are allowing to happen. That's where it gets frightening. Alright. Questions from the audience? Yeah, yeah.<laugh>, I thought one, sorry. Thank you. So one interesting idea that James Lovelock had of a low cost way to reduce global warming would be to force all the airlines to run the intercontinental flights during the day instead of at night, so that the, uh, vapor would have a dimming effect. How, how would that possibly work or not work in the context of solar geoengineering? Yeah, I mean, uh, it, it's, um, it, it, it doesn't, um, uh, the, the, there are, I mean the, the conversation around this is actually more than the other direction whether we should sort of avoid flying planes at night because that has a, a disproportionate warming effect. Um, so, okay, it's the same, it's the same thing. Um, the, the net impact of all the air travel would still be causing warming. You'd just be causing slightly less warming. Um, if you, if you shifted them, um, to the day. Um, if you actually want to get a net cooling effect, you've gotta start chucking additives into the, into the jet fuel and so sos to create, um, sulfur dioxide and hence subsequently sulfate aerosol clouds. Um, so you've gotta actually do something. And I think that's the, that's where it gets destabilizing is because if you are just saying, well, I'm just gonna fly my planes at a different, I'm gonna change my, my, my, my plane, um, planning my, my, my flight track planning to reduce the amount of warming my airline causes, that sounds like the kind of thing people aren't gonna get that upset about. That sounds like a good thing to do, but if you say, I'm actually gonna start actively intervening to cool the planet through adding this additives, that's when you're gonna get star getting blamed for, for all the side effects. Thank you for a very interesting talk. Um, I'm curious how you respond to what, you know, I felt as kind of an increasing rhetorical push from a lot of energy companies arguing, you know, we're, we're getting to net zero, but we're still gonna need fossil fuels, you know, 50, a hundred years from now. Which it sounds like based on, on your talk, you do agree with, but maybe to a different extent than, you know, a, a, a total or something like that. I don't know. I'm just curious how you, how you kind of respond to that rhetorical shift. Uh, They, uh, I I would agree with 'em, we will still be using a hundred, uh, fossil fuels in, in, in a hundred years time. The question is whether those fossil fuels will be causing global warming. They know how to stop the fossil fuels they sell from causing global warming. Um, they're just not doing it. So that's my answer is yes, if you think we're gonna have to carry on using, using these things, then you should be, be stopping them causing global warming. That means disposing of the carbon dioxide that they generate back underground. Um, they say this will happen, but that somebody else will pay for it. That's the, that's the argument. Um, so, so my response to them is, if you want to keep selling your stuff, what's your plan for stopping it causing global warming? And by the way, one of the things I did learn about at sir week, one fossil fuel company in the world does have a plan and has a commitment and are putting money behind it to stop the fields they sell from causing global warming. By 2050, they're gonna be putting a ton of carbon dioxide back into the ground for every ton generated by the fields they sell by 2050, they're putting more, they're putting about a billion dollars into the first plants of this kind in Texas to actually capture carbon milks outta the atmosphere to start putting it back underground. Um, that companies, this is all public. That company is Occidental Petroleum. It also happens to be the only fossil fuel company in the world whose chief executive is a woman.<laugh> observation Someone is asking about nuclear energy, um, no longer part of, uh, those four projections to phase out, um, fossil fuel use energy, 1.5 degrees of warming. Um, is there a fear of, um, nuclear energy sort of justified with You? Yeah, I, I did actually think of having a fourth topic in this, on the nuclear option as it were. Um, and because of course that's another one where you've gotta weigh up the, um, geopolitical implications of a, a nuclear future, um, versus the, the benefits to the climate that would actually be benefits to the climate to, to shifting our energy systems rapidly, um, to nuclear. Um, but of course there are other consequences there, um, by and large, um, at the moment where, where I stand on that is, um, the costs of the, there's, there's cheaper ways of getting to where we need to go. Um, and in particular, fossil energy, getting rid of the CO2 is actually competitive. It's significantly cheaper actually, the nuclear energy at the moment. So nuclear energy has got a lot of work to do to actually even become competitive with, as it were, safe fossil energy. Um, obviously fossil energy dumping the CO2 in the atmosphere is, is the cheapest of of them all. But that's a bad idea. We, we could have kind of agreed that, but even if you get rid of the CO2, um, capture it and put it back underground, you're still cheaper than nuclear energy. And so that's why I think, for example, the amount of money the UK is spending on Hinckley point is ridiculous. They are Questions. Oh, good. Thank you. I'm sorry, I didn't quite understand the fact that precipitation is carrying on at a constant rate, but temperature is going up. What kind of effect is that gonna have on food production? Okay, so, so yes, sorry. Um, I I, I I appreciate the opportunity to go back into that 'cause that was, was the, the bit of physics in this lecture. Um, so, and, and I, um, and, um, the thing is that carbon dioxide's going up at the same time, the temperature's going up and the level of carbon dioxide in the atmosphere has a drying effect, a direct drying effect. Yeah. Whereas temperature's going up, that has a moistening effect because, you know, and, and so at the moment these two things are, uh, competing with each other. If you eliminated the, the point I was making was if you eliminated the warming effect of the, of, of, of the CO2 by some sort of sunshield, um, you would still get the drying effect of the CO2. So you, you would then swap that constant, uh, precipitation with a, a steady reduction in precipitation mission. You know, so farmers are not be happy, so farmers are not gonna be happy. Well, farmers are never happy. I mean, that's, that's a golden rule. Um, but, uh, but, but yes, I mean, you know, we, the, the, the, we are seeing impacts of the climate change. We're already getting on food production and there are side effects of geoengineering on food production as well. I mean, we could, we could, there's, this entire conference is devoted to, you know, quantifying the side effects of, of, of geoengineering. Um, the argument's always made. Yes. But it would be much worse to just let the climate warm up. And the, the, you can make that argument. But the problem is, I don't think that argument will work for the people who feel they're being adversely affected by the global geoengineering program telling them, oh, but you'd be much worse off if we weren't doing it. Probably won't work for people. Um, and that's why I see this as this uniquely destabilizing, uh, idea. Um, I think we might be able to take, um, I'm just going to take one from Slido and then leave it to the floor for, in a global interconnected system, our government thinking about the no, uh, on social and geopolitical effects of climate change, mass migration, refugees, crisis, et cetera, war food shortages, et cetera. Do you think there is an awful, Well, I hope they are <laugh>. In fact, I, I, I hear there's some people hear from the f CDOs, so, so hopefully they're thinking about this.'cause yes, there's lots to think about. We, we live in a, in a, in a, in a highly interconnect world, and these are the impacts that we will become most. And we also live in a corner of the world where we can probably insulate ourselves from the worst debates of climate change. Um, uh, uh, you know, this, this is a part of the world where yeah, you know, we'll have a bit more flooding and that sort of thing, but it's not, you know, it's not the same as the impacts that are likely to happen in say, north Africa or, or, or the Asian subcontinent, um, and, uh, the Indian subcontinent. So, so, you know, I think that's, uh, that's where this, this really fuels this geopolitical tension because if you have rich countries that have overwhelmingly caused the problem, um, putting up barriers to stop people moving from poor countries where these countries have literally become uninhabitable because of, of, of warming, you know, as you see increasing regions of the world, um, you know, we're seeing increasing regions of the world becoming, um, experiencing temperatures where people simply cannot safely work outdoors. Um, if those, you know, were, was, were seeing increasing incidents of this, um, then that's gonna be, that's gonna be difficult.'cause you're gonna be telling people, sorry, we changed the climate. You can't live where you're living, but you can't come to here either. Um, you, that's, I can see that that could end badly. More questions? I think we have the agenda over there. Thank you. Hi. Um, just a thought, I mean, in terms of yeah, sort of mitigating resentment, the fact that there's 1% of the global population can dream 66% of emissions. I think that's about two and a half thousand people in the world according to Forbes, um, rich list or something. But can we just, um, focus on reducing their emissions as opposed Number people, the 1%? Yeah. Um, uh, I mean, if, if the 1% richest people in the world did lots of slightly different things, um, the world would be a very different place. Um, and, but we don't, you know, this, this is, this is one of the challenges we face is we, we can't, we can't control, um, these people. Um, and, uh, and probably we are, I mean, it's the 1% I'm talking about here. So, so a lot of people, I mean, it's probably much of the population of London probably is in, is in that, is in that 1%. Um, so, so, you know, it's important to recognize this is not, this is not a few plutocrats, this is, this is a, a, a large chunk of the world population. Um, and, but yes, I think we do need to think about climate solutions. We need to look at climate solutions to make sure that they're, you know, primarily affecting the emissions of, of the, of the global rich. Um, so sort of back to fixing fossil fuels, for example, I wouldn't turn around to, um, uh, Mozambique who's just discovered oil and gas to say you, um, you have to put all the CO2 from your oil and gas back in the ground. I mean, you know, that's, um, we should do that in Britain first. You know, we, we could do that in Britain. We, we could, we could stop the oil and gas we produce in Britain from causing global warming relatively quickly. Um, in fact, I, I've said this fact before, but it's worth remembering for the amount of money we were paying for gas last year. You could have captured every single molecule of Carbondale outside that gas generated back outta the atmosphere, put it back under the North Sea. So all of the natural gas use in the UK would've caused no global warming whatsoever. And you could've done that twice over with the amount we were paying for natural gas last year. Now, admittedly, we were paying a lot for natural gas last year. That was even with the government price cap. Okay? But that puts it in perspective. This is a fixable problem. But you've gotta somebody, and basically some government has to have the, the guts to stand up and say, no, okay, this is, this is gonna have to change. And we're gonna talk about this, um, in the next, um, shall We take another one? Shall we push? I I, I'd love to hear this question 'cause it's obviously, uh, <laugh> Question fees. How about, uh, something like Lowe's that produce an item or an energy or a gas are responsible for the disposal of, of the effect in the first place. So the Gaar is, may be supplying, uh, a great chunk of the gas we are burning outta Milford Haven and wherever, but they should be responsible for doing the, uh, equation that takes the CO2 produced from their product out of it. Same as if I was to buy a car. The disposal of the car at the end of the day is an issue as well. How about that? That is a genius idea. And I commend you to Alan Frame and Mason 2009 where we suggested the case for mandatory CO2 sequestration. Um, and, uh, um, and I can also, so we called it the carbon takeback obligation, or that's, that's its new name. And ultimately, I firmly believe this is actually how we're gonna solve the problem. It's gonna have to become a condition, a licensing condition. If you want to dig it up, you've gotta put it back. And, and it's, it's that simple. By 2050, nobody should be allowed to sell stuff that causes global warming. So if you wanna sell fossil fuels, you've gotta get rid of the CO2, either you own the CO2 or somebody, or go capture it back outta the atmosphere. I don't care, as long as you prove that it's been got rid of, that's, that's the solution. And what was frustrating at Sir Week in Houston was the number of people who I said this to, and they all said, yeah, that's obvious. We know that's gonna happen, <laugh>. Yeah. They said, yeah, of course. And, and when it's compulsory, we'll do it. And I said, would you say that in public? And they said, no, <laugh>. Well, thank you very much for this fantastic lecture for.