 Hello and welcome to our fifth combined naval address on climate energy and the environment. My name is Commander Andrea Cameron and I'm a permanent military professor here at the Naval War College. I also direct the Climate and Human Security Group. Over the last three years, we at the Naval Academic Institutions have been building a network of faculty and students interested in climate and energy topics. This collaboration includes the Naval War College, the Naval Postgraduate School, the U.S. Naval Academy, the Naval Community College, and Marine Corps University. We've had some exceptional national and international academics talk to us about energy innovation, climate communications, analyzing DoD emissions, and Navy policy on climate and energy. Today we're brought together for our next combined naval address and it's on an up-and-coming topic, geoengineering. What is it? What is the world doing about it? Are there rules? And is it ethical? When we talk about climate change and what we can do about it, we broadly have two levers. One is mitigation and the other is adaptation. Mitigation is about reducing the greenhouse gases in the atmosphere. Think about alternative energy sources that produce less or no heat-trapping gases. And adaptation is about the projects or programs we have to adjust to the changing climate. Think about coastal resilience and salt marshes or elevating our buildings and our piers. These are examples from Navy Climate Action 2030. Now in the Navy, we are pursuing both adaptation and mitigation approaches, but there's a third possibility. Geoengineering. What is geoengineering? We're going to pick one piece of it today because, broadly, it is a term of art that we use for a variety of climate-intervenged ventures to the whole Earth system. Today we're picking apart solar radiation modification. As we have increased heat-trapping gases in the atmosphere, can we modify the amount of solar radiation coming into the Earth's atmosphere and alter that part of the Earth system? For a long time, most scientists and policymakers have advised caution about geoengineering approaches. This is for both scientific and social reasons. We don't know the second, third, fourth order effects to the system or to our neighbors. There's also a few ethical questions related to manipulating the Earth's atmosphere. However, the motivation for understanding the full range of climate interventions has gotten stronger as the planet continues to warm and our mitigation or decarbonization strategies may need to be augmented. And the only way to know about the impacts is to do more research. And that is why we are here today to discuss where we're at and what kind of research can augment this. Here to talk to us is Dr. Catherine Rickey. Dr. Rickey is an associate professor at the School of Global Policy and Strategy at UC San Diego and holds a joint appointment with the Scripps Oceanography. She is an interdisciplinary climate scientist who combines methods from the physical climate sciences, including Earth system modeling and analysis of environmental observations with methods from decision theory and risk analysis. Her work focuses on a range of climate policy topics, including climate geoengineering, country level economic impacts of climate change, air quality climate tradeoffs and climate policy, and climate driven human migration. Her work has a consistent theme. She looks at the strategic implications of regionally heterogeneous climate outcomes and quantification of decision relevant uncertainties. Her background as both a physical and social sciences make her an ideal speaker for the questions we have today. Her mission to great research and academia is informing policy. Dr. Rickey was part of a 2021 National Academy study committee on designing a solar engineering research agenda and formulating principles for research governance. This seminal report informed the recently released White House's Office of Science and Technology Policy research plan that was required by Congress. Additionally, Dr. Rickey is a member of a multidisciplinary expert panel convened to provide a rapid review of solar geoengineering science to the UN environment program. Overall, she understands both the science and the issues facing the governance. I'd like to thank Dr. Kate Rickey for joining us today. And I will turn the floor over to her to share her presentation and lead us through the discussion. Great. Thank you so much, Professor Cameron. Good morning, everyone, our afternoon where some of you are. I'm really happy to be here today to introduce you to this topic. There's a lot to say about climate geoengineering in 25 minutes. So I'm going to try and cover quite a bit of territory to give you the context that you need to start thinking about this topic. And then hopefully we can have some good discussion afterwards. Okay, so I like to always put this doodle on my first slide. It's an illustration that an artist made for a piece that I co-authored in Foreign Affairs about geoengineering back in 2008. And I think thematically it sort of is illustrative of a lot of actually the social concerns about the set of potential technologies. So the context that all of this is occurring in really is about the fact that progress at the international and national level in responding to climate change right now is very slow compared to where impact scientists have told us we need to be. So this is, these are a couple of figures from the most recent UNEP gap emissions gap report. On the left, we have a figure that shows us where we're headed in terms of emissions reductions, according to the commitments that people have made under the UNF triple seed. So the big international climate agreement. So if you look at the top line in the spot you can see where we would have been if the international commitments that people have made and the policies to avoid climate change that are underway hadn't happened at all. So the first thing to say about this picture is that we have started making some substantial progress towards managing climate risk through reducing greenhouse gas emissions. However, we're, we're way off target from where we need to be in order to meet some of the temperature targets that were laid out in the Paris climate agreement, the two degrees and 1.5 degrees. So you see where we are with this top blue line under current policies the orange line tells you where we'll end up if people meet their meet their obligations that they've put forward under the UN and nationally determined contributions so voluntary commitments to reductions in greenhouse gas emissions and a slightly more optimistic interpretation of those in the red line. And then you can see the very large reductions in greenhouse gases needed to meet these ambitious temperature targets. And on the right you can just see even even within these given emissions scenarios there's a lot of uncertainty about what the temperature outcomes are going to be. So geoengineering the idea of it the discussion around it this really taken off is all occurring within this context and and what geoengineering is is basically a very broad class of speculative technologies mostly these things don't exist yet that have been proposed in order to counteract effects climate change by removing carbon dioxide from the atmosphere that's called CDR I'm not going to talk about that much today, or by directly modifying the Earth's energy balance at a large scale and this is something we call solar radiation modification or SRM or I'm going to use the term solar geoengineering, which is what we used in the National Academies report and just more use what I'm more used to saying. So there's two types of geoengineering, and the first type is these interventions into the Earth's carbon cycle in order to try and take CO2 out of the atmosphere, more quickly than the carbon cycle would naturally. And that manages climate risk by removing the root cause of the problem. The other type SRM works by reflecting sunlight in order to cool down the planet to counteract the effect of greenhouse gases, and I want to just walk you really quickly through the basic physical idea behind how this works. So basically the Earth's climate system, this is a little doodle that shows just at the global level, what's going on with how the Earth responds to the energy it's receiving from the sun. So this incoming yellow beam in the middle of this little doodle shows you the sunlight that drives all of the ocean and atmospheric processes here on Earth. About 30% of incoming solar radiation is reflected back into space before it's absorbed by the Earth, and about 70% is absorbed by the Earth and reemitted by the Earth according to its radiative properties. So the sunlight has very different properties in terms of the radiation than the radiation of the Earth that gets reemitted. And the atmosphere is actually transparent for the most part to solar radiation, or we often call that shortwave radiation in the physical sciences. And then the atmosphere is partially opaque to the long wave radiation that the Earth reemits back towards space. And so as a result of that opacity of the atmosphere in the long wave spectra, the Earth's atmosphere sort of recycles this energy that's emitted by the Earth and the Earth warms up as a result of it. Now that's a good thing at some level because otherwise Earth would be really cold without this recycling effect. But when we add greenhouse gases like carbon dioxide to the atmosphere, we warm up the Earth as a result. So to warm the Earth, you add a gas like carbon dioxide and that enhances this recycling power of the atmosphere. And catches that radiation emits part of it back towards the surface of the Earth to warm it again rather than letting it escape to space. Now if we want to cool down the Earth, we have a couple of options. We can remove greenhouse gases from the atmosphere, or we can instead increase reflectivity of the Earth that we call this albedo. And if we decrease the amount of sunlight that gets absorbed by the Earth, then the atmosphere doesn't get the chance to recycle it and warm up the surface. And so the way that solar geoengineering works is that instead of removing these greenhouse gases and addressing the root cause of the warming that's occurring right now on Earth, we would counteract that warming by reflecting more sunlight back into space. So we take this long wave effect of warming and we cancel it out with a short wave effect by reflecting solar radiation. So this is why we call it solar geoengineering or solar radiation modification. We are attempting to moderate this warming by increasing that amount of sunlight that the atmosphere and the Earth's surface reflect back into space. And what this figure shows is sort of the three main approaches that scientists are most seriously studying right now to do this. Starting from the top here, a stratospheric aerosol injection is an approach that mimics something that we've already observed as climate scientists in the past. And that's when there's a large volcanic eruption and a bunch of material, including aerosol precursors gets blasted up into the stratosphere. We've actually observed the climate cooled down, the Earth cooled down after events like that. And so that's because the stratosphere is a layer of the atmosphere that's convectively stable. So when things get up into the stratosphere, they tend to stay there for a long time. Aerosol particles, small particles form and they're very effective, these aerosols at reflecting sunlight back into space before it can get down to the surface of the Earth. And so probably the approach to solar geoengineering that people are most confident would actually work right now is this stratospheric aerosol injection. People also talk about something called marine cloud brightening, which is an approach that would enhance the reflectivity of low marine clouds by inserting particles into the clouds, making the droplets smaller and increasing their lifetime, such that they would reflect more sunlight back into space as well. So the type of cloud that on net tends to have a cooling effect on the planet. There's one more approach called serious cloud thinning that people are looking into a little bit as well, a little less optimistic that it would work the way we want it to. But this approach modifies a different type of clouds called serious clouds and seeds them as well. But serious clouds actually have a net warming effect on the planet. And so by thinning out the serious clouds, we allow more long way of radiation to escape to space, which also cools the planet. That's a little differently than the other two approaches that people consider right now to be a little bit more feasible and likely to work to pull the planet. Okay, so that's basically what solar geoengineering is a very quick introduction to what people are talking about when they when they say SRM or solar geoengineering. Moving into understanding sort of what it means and how we interpret it and how it fits into climate risk management proposals. It's important to understand that compared to the other body of climate science that we use to try and understand risk and figure out how to manage it. Solar geoengineering research is fairly new on the scene. So the fast the vast majority of papers on SRM have been published in just the last 10 years. And this is a figure from our review paper that some colleagues and I wrote recently. And so you can see some landmarks on this timeline for papers that were published that are important to solar geoengineering, but an important piece of context here. This is 1988. This is the year that Dr. James Hansen testified to Congress, a very famous event in sort of climate science and policy. He testified to Congress that fossil fuels were going to cause dangerous climate change and that we needed to do something about it. The reason it's kind of considered a landmark is because he was basically, you know, speaking for a large consensus of the scientific community. There was a lot of climate science already about greenhouse gases effect on the climate by 1988. So you can see compared to the very long history we have of understanding greenhouse gas effect on the climate, the climate system. What we know about solar geoengineering and the level of research that's been done is just a tiny, tiny fraction in comparison. The other important thing to understand about SRM research is that it's mostly been Earth system science. So more than 75% of the papers that have been written, the peer reviewed papers that have been written about SRM have been in the physical or system sciences. Despite the fact that we know it's not just physical uncertainties that are going to drive some of the thorny decision making issues around these proposals, but also social uncertainties. Social feasibility is a big question mark as well. And so you can see, for example, the body of research about the political, the political implications, the international relations implications, the psychology of how people respond to these proposals, a much smaller body of research today than the physical science. So, but what do the earth system models the earth system science that has been done, what do they tell us about what we might expect to see. Now I think when this work started being done in earnest, you know, 15 years ago, there was an expectation that because of this mismatch between the long wave and shortwave radiation that solar geoengineering really wouldn't work very well at the regional level to manage climate risk. Earth system models in the last 10 years have actually sort of revealed that geoengineering looks like it was solar geoengineering looks like it would actually work pretty well in a lot of ways to counteract the warming from greenhouse gases. We show maps of simulation results. On the left, we have the changes we expect to see around the globe with one degree of warming from CO2. That's the temperature changes on the top precipitation on the bottom. And then on the right side with simulations tell us about what the things would look like around the planet with one degree of warming from CO2 offset by one degree of cooling from stratospheric geoengineering. And what you can see is that it actually does a pretty good job at reducing warming, most places actually around the world. So if you look at the figure on the right bottom corner, you see that the residual or the remaining precipitation changes after you cancel that global warming are larger. And so there's some impact implications of that. I think, you know, people have found that in earth system models this works a little bit better than climate scientists hypothesized when this line of research was getting started, but it's important to recognize that solar radiation modification is never going to compensate for greenhouse gas driven warming perfectly. And this again has to do with the fact that you're canceling a long wave radiation forcing with a short wave radiation forcing. And so what that means is even if you cancel out global temperature change perfectly that you're still going to have changes in the vertical structure of the atmosphere. There are differences in general atmospheric circulation. And so you can never get it right because there's that physical mismatch that's always going to get in the way of getting a perfect cancellation. Okay, so we know what solar geoengineering is. We know that it's mostly earth system science has been done. And we know that the physical effects are never going to cancel out the effects of greenhouse gases perfectly. So let's think about the social context a little. There's been all of this earth system science still a lot less than about greenhouse gases, but most of the science has been on earth system science, most of the work has been on earth system science. And so we have all of these papers that have been written about oh how do we make reflective particles, how much sunlight would be reflected, how much would this curl the earth what are the regional effects, etc. So the issue with this body of work that's already been produced is that there's an important social studies and social context that sandwiches these earth system studies. And in order to interpret what they mean you really need to understand these, these pieces of social science that have to come before and after system science as well. Leading in to our system science is a bunch of assumptions about the socio political background conditions about what our actual objectives would be if we're doing solar geoengineering about social feasibility legal feasibility, and the way that we operationalize those assumptions in order to feed them into earth system science are through scenarios, and the scenarios that have been examined to date are pretty limited. After then we crunched our models, etc. are physical models. Then we need to take those results from earth system science and do impacts assessment in order to then be able to interpret why we care. What does the economic impacts be what does this mean for equity what does this mean ethically what are the governance constraints required. So really the interpretation of all this physical work. It depends on things that come before and after outside of natural sciences and we know from looking at that plot of what the what science has been done, that a lot of this analysis is pretty sparse at the moment. Okay, so just to hone in a little bit on this top part of the sandwich first and then I'm going to talk a little bit more about the bottom part of the sandwich. Basically, the people recognize that the for solar geoengineering decision making the climate context is going to matter a lot so the way that it would be implemented will influence the outcomes. So sort of the best case scenario that people talk about for a counselor geoengineering would be used is a sort of what's called a peak shaving scenario. And that looks something like this in which we're living in a world where initially we were on this red trajectory business as usual. And then we use mitigation technologies to cut emissions aggressively. That's going to bring down our global temperature trajectory, manage our risk that way. Then we use carbon dioxide removal in order to speed up that or carbon cycle process brings you to another greenhouse gases out of the atmosphere, manage our risk that way. And then we would just use SRM to sort of tide us over until those things actually work to bring down global temperature since those processes are slower than solar geoengineering, which works within days to one or two years relative to the many decades that we need in order to get temperature change from mitigation activities. Okay, but so that's the best case scenario. Another way that people talk about using solar geoengineering is just to give a helping hand to adaptation activities. So in this case, it would be we use solar geoengineering on top of emissions reductions, but there's no carbon dioxide removal because a lot of these carbon dioxide removal proposals, they haven't been tested. They don't exist yet either they haven't been scaled. And so maybe they don't work out. So another way people talk about using solar geoengineering is to just reduce the rate of warming in order to have more time to adapt to climate change. Another way that we could end up using geoengineering is it's just we don't get our act together. We don't do mitigation, we don't do CDR, we don't have sufficient adaptation and so solar geoengineering ends up being used as an emergency response. So it might look something like this right or actually if it's truly an emergency, we might get something like this deviation from business as usual right where we're like oh man this we things have gotten way too warm we've got our wildfires going. Our tropical cyclones are too strong, etc. We need to do something now. And, you know, we're sort of figuring it out as we go. And then finally I wanted to say something about this scenario which is has been discussed, and it's sort of the one of the biggest concerns out there about solar geoengineering, which is this concept of moral hazard and this is the idea that geoengineering could potentially feedback, or even the idea of geoengineering or the possibility of it could feedback into what we're doing in other ways to manage climate change related risks. This is something that people refer to as moral hazard, or mitigation deterrence sometimes. And the idea here is maybe we would be managing risk a lot with mitigation, or carbon dioxide removal. And because the solar geoengineering option exists now, we, instead of using SRM for peak shaving, we start managing climate risk less with these other tools, and these sort of feedbacks, the socio political behavioral feedbacks that could influence these outcomes, haven't really been explored very well yet. We also haven't really explored in the physical sciences, even what different sort of approaches to solar geoengineering that are more regionally focused might look like. So we know that political contexts will matter for scenarios as well. And so there's been some studies that show that a regional approach to trying to optimize regional outcomes would have very different global outcomes. So for example, and there's been very little research on this. For example, a study on just trying to cool down the Arctic had the result that Arctic cooling would shift precipitation in the tropics to the south of some work we've done in my group where we've tried to do marine cloud brightening just to mitigate very extreme heat events in the western US. What we found is that disrupts weather in Europe and fiddles with ocean overturning in the Atlantic. We did another study in my group where we tried to reverse a drought in the Sahel region of Africa using geoengineering and we found that we could do that, but it caused a drought in Sub-Saharan East Africa. And there hasn't been a lot of exploration of this regional scenario space yet either. On the other end of our sandwich with the impact assessment that allows us to interpret our Earth systems science and figure out why we should even care and how we should make decisions. The work here is also very sparse. I'm just going to cover a couple of things because I want to make sure that I don't go over time here too much. But a really important piece of context when you start thinking about the impacts of these activities is that right now we're living in a climate science world where a lot of impacts assessment. And a lot of the conversations about how we manage climate risk has been characterized in terms of global temperature management. And so this is a figure from the IPCC special report on 1.5 degrees. So the 1.5 degree temperature target that was put into the Paris climate agreement. And the scientific work that was done in response to that and this has kind of continued since then has characterized climate risks in terms of constraining net global warming. So this figure shows a bunch of different risks associated with climate change and how they connect to global mean temperature change because now we have this international policy framework in which the main thing we're trying to do is limit global mean temperature change. So risk goes up on this plot and risk is linked to global warming. Now this works really well if the way you're managing climate risk is with mitigation because as you do more mitigation you reduce global temperature and you reduce risks and we've put all of these risks in terms of global temperature. Now the problem is solar geoengineering doesn't change global temperature in the same way that reducing greenhouse gases does. And so actually the risks associated with different sectors and different regions with solar geoengineering at a given global temperature reduction might look something like this instead. And so in order to understand what the impacts of solar geoengineering would be you actually need to do impact studies that are specific to solar geoengineering. And right now the detailed regional studies of what solar geoengineering effects would be that would need to feed into that work are fairly limited. So for example, you know this is a review paper that we worked on that showed sort of what sort of hydrological details studies have been done for different regions, and certain regions just haven't gotten a lot of attention yet in terms of understanding what the precipitation responses the soil moisture responses runoff so water availability on soon all effects have been. And we need those types of studies in order to understand things like what would happen with human health. There's only been a few studies on the impacts of solar geoengineering for the implications for human health so far. So just for example, the study that was published in 2022 suggests that that solar geoengineering could redistribute malaria risk, so it would reduce the risks of malaria in certain areas of the world and increase them elsewhere. So again, this, you know, just one study, and there's not a large enough body of work to know whether this study is robust. We can see, we can see that already with, if we look to sort of the impact studies that have been done on solar geoengineering potential effects on agriculture. We're doing a little bit better. We have several studies less than 10, but there's mixed results here so for example a very high profile study done in 2018 suggested that if you did solar geoengineering you would get some benefits to crop yields by reducing the global temperature change that's expected from global warming so you get benefits relative to a high greenhouse gas high warming scenario, but that those benefits get canceled out by the effects of reducing the insulation that plants need the sunlight they need to grow. On the other hand, another study in 2021 doesn't find this effect. So they actually find that solar geoengineering on net would have a positive impact on crop yields. So we have this set of evidence that's not large enough yet to know which results are robust. We look at things like economic studies. There's very few studies that are empirically based about economic effects of solar geoengineering so far. So this is a study that my group did in 2020, where we took the empirical economic models that people have been using to extract the economic effects of greenhouse gas emissions, and we applied them to solar geoengineering to see what we would find we simulated the economic effects of some very stylized geoengineering scenarios, including this scenario. On the left, you can see what we simulated in terms of global temperature change over time on the left and you see this blue line actually shows we asked what would happen actually if we used solar geoengineering which we have a lot of leverage potentially how we would use it. What if we used it to actually over cool the planet, instead of global warming we implemented global cooling. And what we found for that situation is that if you over cool the planet you consistently reduce inter country income inequality. But the magnitude of these effects is really dependent on on the impact function model specification you use so the statistical model you build. So there's still a lot of uncertainty about what the exact economic implications of this are. So there's been very little game theoretic work on solar geoengineering, but what has been done so far shows that the strategic incentives that are expected with solar geoengineering activities would be very different than the strategic incentives that we understand associated with mitigation gas reduction activities. So in a mitigation game this is pretty well understood, you know reducing emissions is expensive it's expensive to transfer to transform the global energy system. And everybody wants as much mitigation as possible but they want other people to pay for it and so there's an incentive to free ride right. In a geoengineering game geoengineering is actually expected to be a pretty cheap relative to emissions reductions, because you only have to put a little bit of material in the stratosphere it stays up there for a long time for pretty big cooling effect. The exact costs of solar geoengineering are expected to be a lot lower than the cost of mitigation per degree of global cooling you get. And so because cooling can be achieved at a relatively low cost. And because solar geoengineering doesn't cancel out the effects of greenhouse gases perfectly the preferences for how much you do diverge between different places. So the incentive for solar geoengineering is to exclude from decision making as much as possible which is very different than the sort of inclusive coalitions, you'd like to build for mitigation in order to share costs. And so we have some game theoretic work that we did examining these incentives and that we what we found is that, you know, countries and regions prefer to build the smallest coalition possible, and keep decision making within the smallest group they can get away with in order to optimize to the extent possible the global climate outcomes for themselves. The main takeaway and this is a quote from the National Academy's report that I worked on here, is that research that has been done to understand the magnitude and distribution of impacts on ecosystems, human health, political economic systems. And these issues of societal concerns so the bottom half of the bun. This is a very nascent area of research and the studies that have been published so far are not going to provide us with a sufficient basis in order to make good decisions about solar geoengineering. And so the National Academy's report that I worked on was really about trying to identify the research that we really need to do and one thing that we recommended is that we really need to invest in social science research, and it needs to be integrated with a physical science research better. Okay, so, finally, solar geoengineering from a decision making perspective is really about risk versus risk assessment climate change caused by greenhouse gases is presenting tremendous risk to society. It's going to become more and more disruptive, and solar geoengineering is very risky as well we don't understand it, it's not going to counteract greenhouse gases perfectly, there might be some negative side effects. And so what we need to find out is whether the risk of doing solar geoengineering is worth the risk reduction we expect associated with lower warming that's caused by greenhouse gases. And now we face a lot of challenges here and doing good risk risk assessment. And some of them include that there's a lot of dimensions of analysis that we need to go through. So we need to understand the climate context and there's a lot of possibilities for how things could play out in the future. We need to understand all these different options and what their effects would be what their associated risks would be. And so reducing these dimensions in a, in an understandable way is a big challenge for risk risk analysis. So there's this thing called deep uncertainty that's going to be associated with certain things we would like to know ideally about solar geoengineering, and that even with a lot of additional research there's going to be significant impacts that remain when we might need to make a decision about SRM. And then finally, we have this problem of very diverse risk perceptions about the use of proposed technologies like this or even doing research about it. So climate change effects with or without SRM are not going to be distributed equally we already know this around the globe, and the risk perceptions the risk related values are going to vary a lot between nations and even communities within nations. And so this is sort of just an introduction to some of the issues associated with these proposals. If you'd like more information I really recommend checking out this National Academies report that I worked on with a number of really great scholars and members of civil society organizations. I think some of the conclusions from that report that the scientific understanding is really limited fragmented more research is needed that there's no systematic governance structure that exists right now to deal with research or deployment of these that the goal of research should really be to characterize and reduce uncertainties for decision making, and that we really need research that's multi disciplinary trans disciplinary involves decision makers and civil society, and that's international because if the research is not international, it's not going to be, it's not going to have the legitimacy it needs in order to deal with these social feasibility problems. And that, you know, finally, that we in our judgment in our expert judgment that because of the urgent growing risks from climate change is important to understand solar geo ensuring better. Because we recognize that it's never going to be a substitute for mitigation, it's just a potential additional strategy for managing climate change related risks. And in addition, there's this report that was published through UNEP that I was a part of as well that has a more international perspective on some of these issues that also recommends research research assessment and a more inclusive international approach to research. Okay, that's what I have to share with you, and I'm happy to take questions now. Thank you so much Dr Ricky. We have two student questions for you today. First, I'm going to go down to the Naval Academy, and we have midship and second class Cody little prepared with a question for you. Okay, Katie. Yep, do you want to just getting Katie up here, and he'll have your question. Thank you, Dr Henderson. So, yeah, so we're all set to go. Okay. Hello. So what do you say about the like possible concern with geo engineering affecting precipitation patterns for the future. What do I say about the potential of concern for that about that. Yeah, I mean, I think like I hinted at the end of the talk. This is really about comparing the risk of climate change with the risk of solar geo engineering. And because of the physical nature of the climate system, these hydrological effects are always, there's always going to be residual hydrological change. So there's a few things you need to figure out. Are those residual hydrological changes, damaging in terms of the things that we care about. And are those residual changes, posing a bigger risk to society and natural ecosystems than the risks of climate change. There's we're sort of entering a world where there's no great options. And so it's really about making decisions based on what we think is the best bad outcome. And so that's what I'd say about these changes. We can understand them better. We can do more impacts assessment to sort of figure out what the implications are. And then we just are eventually are going to have to figure out a way to make tough decisions about about these potential options. Yeah, does that help. Thank you very much for that. Yeah. Some of our midshipman will have to go on to class now, but I'll just give you a quick pan. Hi, take care. Thank you to the Naval Academy. I'd like to next go to a Naval War College student, Commander Nick Cadillac. Thanks, Professor Cameron. Dr. Ricky, thanks for your presentation. Absolutely fascinating. Last month, the UN Human Rights Council released a report on the potential impact of geoengineering on human rights. And I'm just wondering what role, if any of you think human rights issues will play in geoengineering debates and decisions. You know, it seems like it's an issue that could cut both ways. On one hand, geoengineering could be deployed to protect human rights, like the right to clean environment rights related to food, water health. But on the other hand, some of the potential spillover effects could actually negatively impact those same human rights. Do you think human rights will play a role in these discussions? If so, how much? Thank you. Yeah, thanks for that question. It's a really good one and one that's very central to the discussions around these technologies. One of the biggest and it's certainly legitimate concerns around any potential use of solar geoengineering is questions of equity and who decides. Because of these uneven effects of the solar geoengineering cancelling out greenhouse gases, because of the almost certainty of different preferences for how and how much solar geoengineering we would do, there's this question of who's going to get to make the decisions. You know, if you look at this in sort of like a realist international relations perspective, you know, people say, well, of course, you know, the most powerful major actors always tend to make decisions about these things. And that means that, you know, the poor and the vulnerable and less powerful are always going to get left behind. It's hard to say. It depends on sort of how the international governance conversation and environment evolves in the coming years around this. You know, again, a lot of this does come down to the risk-risk trade-offs. One thing that I'm involved in right now is some work that's been going on for the last decade, but it's been really picking up steam. To do capacity building in the global South and developing world in order to, you know, get scientists in countries in Africa and South America, in South Asia, publishing and engaged in international scientific conversations around this. And that should hopefully increase the chances that a diversity of voices and opinions are involved in the decision-making and whatever international governance constraints get put on solar geoengineering. And I also should build a legitimacy for advising that happens in these countries about how policy makers, how decision makers should respond, because in a lot of places people are a little skeptical about research that's solely produced in North America and Europe, because that's most of the research on this technology so far. And so I think that how these things play out and how much support goes for capacity building is going to make a big difference. And that's why I believe in why in the academies report in the UNEP report we really recommended and insisted that it's important to make this scientific process more international. Thank you so much. I, this concludes the combined naval address but I would like to thank all of the events staff that put this together. And on behalf of all five of the Naval academic institutions thank you so much for joining us Dr Ricky for this talk on solar geoengineering. It's been a wonderful presentation. My pleasure. This concludes the presentation for the faculty who are staying on for the faculty roundtable. We will take a quick break and reconvene at 1430. Thank you.