 Good afternoon. My name is Alex Reich and I'm pleased to welcome you to the National Academies of Sciences, Engineering and Medicine, and to the fourth event of our monthly webinar series, Climate Conversations, Pathways to Action. The National Academies provide independent objective advice to inform policy with evidence, spark progress and innovation, and confront challenging issues for the benefit of society. In keeping with this mission, we're excited to host these conversations about issues relevant to national policy action on climate change. Our conversation today will be recorded and made available on this webpage tomorrow. We won't be taking questions from the audience, but we would appreciate your feedback and your ideas for future conversations, which I invite you to share after the event in the survey linked just above this video. Above the video, you'll also find a link to register for our June 17th climate conversation on infrastructure, which is moderated by Mariette DiCrescina and featuring John Anderson, President of the National Academy of Engineering, and Thomas P. Bostic, a former commanding general of the U.S. Army Corps of Engineers. They'll discuss the different kinds of infrastructure and systems susceptible to climate impacts, the wide range of engineering solutions that can play a role in building a resilient and net zero future, and the future will prepare the next generation of engineers for such a monumental task. But today, we're going to discuss a very different type of engineering, solar geo engineering, and the possible risks and benefits of considering it as part of a portfolio of responses to climate change. In order to be joined by Frank says no director of strategic initiatives at the George Washington University's School of Media and Public Affairs, and an Emmy award winning journalist with over 30 years of experience reporting from around the world on climate and other issues. Frank will introduce our conversationalists and moderate the event. Thank you again for joining the National Academies for climate conversations. Frank, the floor is yours. Alex and thank you so much everybody for joining us today I can't think of a more fascinating and important conversation at a more fascinating and important time with more fascinating and important experts and panelists to join us. Alex mentioned I've done a lot of work in climate and I certainly have George Washington University I started a project called planet forward not long ago. Before that project recently I had the opportunity to interview the new administrator of the environmental protection agency. I pointed out to him that we have broken through all sorts of records with he extreme weather melting ice, and I asked him, is it too late. He said no it's not too late, we are resilient, and we are good at this. This is going to require immense imagination, creativity and invention and research, and that's what we're going to talk about today. And so it's a delight and a pleasure to introduce guests who will join us, the experts, you know them I'm sure many of you, Marsha McNutt she's a geophysicist, and she happens to be the president of the National Academy of Sciences Hello Marsha. Hello Frank, thank you so much for moderating this very important discussion. Well it's a it's a real pleasure I should point out to everybody that from 2013 to 2016 you're editor in chief of the science family of journals from 2009 to 13 director of the US Geological Survey, and you chaired the 2015 National Academies report, which was entitled climate intervention, reflecting sunlight to cool earth so we got a lot to talk about right. Yes, definitely. Chris field also joins us hi Chris. Hi Marsha. Hello Chris. Chris is the perio McCarty director of the Stanford Woods Institute for the environment, Melvin and John Lane professor for interdisciplinary environmental studies. Chris your research focuses on what climate change and you're very focused on solutions. Understanding impacts understanding solutions. The 2021 National Academies report, which was entitled reflecting sunlight recommendations for solar geo engineering research and research governance so this is going to be a very, very interesting conversation with people who literally are the authors and subject. Let's just start. I'm sure that our audience runs the gamut from people who are super expert in this to people who are merely fascinated by it, and those who who find it very interesting but may not be steeped in it so let's start with defining. What is solar geo engineering, and how did you get involved with it Marsha you want to go first. So, solar geo engineering is a grab bag term for any of a number of techniques to moderate how much sunlight reaches earth surface to warm the planet. And as we go on today we can discuss what some of those approaches are, but in general it's any way to mitigate how much solar warming, we receive at the planetary surface. And how did you get involved with it. So, I really was not involved at all. My work is mostly on the solid earth solid earth beneath the oceans. And that I work a lot on volcanoes. And it turns out that knowing something about volcanoes is important to understanding what the possible impacts could be of solar geo engineering. Well mountain to I was seeing up CNN when that mountain to go happen, how much that affected really the whole, the whole world. Chris, how about you what what what you have a quick definition that you go by here and how did you get connected to this. What I think about solar geo engineering is, is changing the fundamental equation that's driving climate change, got energy coming in and energy going out greenhouse gases change the energy going out. So the geo engineering changes the energy coming in. And it is a set of ideas, Marsha says a grab bag that are not well understood, but open up some interesting sometimes terrifying possibilities for how we might think about the earth system in the future. And I'm interested in solar geo engineering, primarily because I care about the portfolio it's not that I'm so much an expert in this particular set of ideas, but I care about the overall and how this might fit in. And I should say at the outset and correct me if I'm wrong both of you but you comment this not as advocates for this but as researchers and scientists interested in this, correct. I'd say, I don't, what before I took part in the 19 or the 2015 Academy study. I knew very little about solar geo engineering about the various approaches. I certainly had not done personal research in it. And I guess I'd say I just didn't have a dog in the fight. I didn't have any strong predilection on which way the report should go. And I think that's what the Academy tries to do when addressing controversial topics is find people who are unbiased and open minded. Let me turn to you and ask you very quickly what the high point of the 2021 this new report is and what you're trying to touch on the fundamental question that we were asked to address is, does it make sense to have a research program to further explore the question of whether or not solar geo engineering ought to be further considered for a place in the portfolio of climate change solutions. The committee came back with a recommendation that there should be a research program at the level of the US federal government with international participation and really robust governance. So let's talk about here today. What is solar geo engineering. What are the controversies questions pushbacks, and what should that research agenda look like we should develop it. Where should it go. Marsha, how does solar geo engineering fit into this, the larger conversation about climate change and responses to climate change because that's a big one now and we have an administration that's really leading it. The way I like to describe it is we have three potential actions we can do. One is to adapt just by moving away from coastlines and better securing our systems for droughts and floods, things like that. We have to adapt to it. The, the best approach is probably mitigation, and that is to stop releasing these greenhouse gases at their sources, or collect the CO2 back after it is released so that it doesn't warm the climate. The third is this category of climate interventions that is once you already get to the point where it's too difficult to adapt, and you haven't mitigated. And the situation is so bad. What can you do to try to lessen how bad it is by some sort of band aid, and the band aid is solar geo engineering. Is it another band aid or another type of intervention like that, carbon capture and storage and that kind of thing. It is. But I would say it's less controversial because, of course, it is more expensive to capture the carbon after you've already released it. It would be much better just to not release the carbon in the first place, from an early point. But at least once you've captured the carbon, if you securely store it, you've actually helped the problem. The issue with solar geo engineering is that the CO2 is still out there in the atmosphere. You've lessened the solar energy reaching earth, but you once that solar geo engineering stops, the full force of warming from the CO2 you've released comes back at you. Whereas if you stopped doing carbon capture, you don't suddenly get a step up in impacts, because you stopped the way you do with solar geo engineering. Let's help us out with some terms here and some things that people who do follow this may have heard and some will understand and some will not. Solar geo engineering versus solar radiation management. Albedo management versus climate intervention. A lot of things going on here. You know, I can also open an umbrella and shift yourself from the sun and feel a little cooler. I'm not going to help the planet very much though. I think that the scientific community has not done itself any favors with this proliferation of concepts that are all bundled under this idea of geo engineering. For example, the carbon dioxide removal that you and Marsha have just been discussing is also often called geo engineering. I think that the important thing in the space we're talking about now is that it's mainly modifications to the atmosphere or to clouds in order to allow less solar radiation to reach the earth surface or to facilitate the release of heat through the atmosphere. And the difference in the terms, I think is mainly intended to make people more or less comfortable as people who are strongly opposed to further thinking about the technologies, tend to think of sort of catastrophically oriented opinions and people who are more advocates tend to think in terms of more of this is another kind of friendly technology, but they're all the same basket of ideas that build on this site, the concept that we've seen volcanoes produce significant amount of is that something we should consider trying to do proactively and it's immensely complicated and engaging the public and communicating with the public is immensely complicated. I mean my goodness if we've had so much trouble asking people to wear masks in the midst of a pandemic, if you're trying to find out the solar geo engineering, what however you frame it whatever terminology use clearly is fraud and we'll get that really important theme in the 2021 report. Social feasibility is if anything even more complicated than the technical feasibility, and it needs to be researched at the same time it's subject to robust governance. Before we go to some of the controversies and really hard lifts around solar geo engineering. Marsha quickly back on the 2015 National Academies report. What were the key themes there and then Chris to you and you may want to talk a little bit more about that social component. The key themes in the 2015 report were that basically, we don't know enough about what the impacts are of purposeful solar geo engineering to actually say, with any confidence that the cure is better than the disease, if the disease is transforming. We felt that there were possible unintended consequences. And so that's why we recommended a follow on follow on studies to actually research these technologies so that we would, if, if the time came, and our back was against the wall, we would know whether this was worth pursuing the second thing we said is that there are no international laws or treaties right now that would prevent any actor from unilaterally geo engineering the globe. And because of that, we needed to know better. First of all, how we would detect a solar engine geo engineering event if some nation decided to do it because they didn't like the current climate. We also would have a very difficult time attributing impacts to that event. And that's why we need more research. Plus we need governance. There are currently no laws that prevent any nation or any individual corporation for example, from from going ahead with geo engineering through some sort of solar radiation. I mean, you've just laid out a really horrific and probably very effective James Bond movie right some rogue state or actor, geo engineers the world and how do you know and what do you do. Chris how about your report where did you go from 2015 to 2021. My question for the 21 reporters, should we do more research to figure out whether we ought to be further considering this. And how should we govern that research. The starting point was very much the conclusion that Marsha just emphasize that the best way to tackle climate change is to decrease the emission of the greenhouse gases, and to invest in adaptation so that for the climate change to avoid people and ecosystems and cope with them as as effectively as possible. But in addition to that and especially because the impacts of climate change are advancing so rapidly that we really need to have a clear understanding what the whole portfolio of possible solutions might look like and whether there's not for geo engineering. So we outlined a framing for an approach to figuring out the answer to that question, figuring it out in a way that empowers the, not only the scientists but the global community to have access to this information to have a role with all different levels of society all around the world and in figuring out how that information is used, and in making sure that the science is serving the public interest and not going off on its own. We'll talk some more about how that science would serve the public interest and be pursued but let's climb into some of the very considerable concerns and controversies around all of this. You said Marsha earlier that if our back was to the wall there are those who say that this essentially would be like raising the white flag on mitigation that this doesn't address causes of climate change, fossil fuels deforestation methane from landfills agriculture, and so much more so and what is the response to that I mean how do you, how do you respond to that. Well, I don't think anyone disagrees with that viewpoint, but our committee basically said that for decades now, science has been raising the specter of unacceptable climate warming and urging mitigation. And yet, we are digging ourselves into a deeper and deeper hole in terms of the projected climate warming right now. There are numerous nations that have stepped up and really worked hard to reduce their emissions and change over their energy systems. Nevertheless, we still see some countries building coal fire power plants today, and the coal fire power plants are the worst CO2 emitters in our energy systems. The problem is that it's just a difficult problem to change the foundational energy systems upon which society depends in any short time period. And so we, it's it's sort of like the analogy I use which is very US centric is no football wants to be down six points in the fourth quarter with four seconds on the clock. Is that where we are now. Well, we're getting, we're getting, we're getting pretty close to it, but every team, every team practices, the Hail Mary pass in just in case that they are, and that's what we the Hail Mary pass this would be the Hail Mary. Chris, what about the comment slash criticism that for example solar geo engineering doesn't address the flip side of the climate coin or maybe it's the same side ocean acidification right because just with solar geo engineering help us with that part of climate change. It's a really important kind of core feature of this whole conversation is that solar geo engineering is not a comprehensive solution. It doesn't address ocean acidification it doesn't address the changes in the atmosphere. It could have a whole range of side effects that are poorly known including changes in, in weather patterns and distributions. And it could erode the amount of ozone that's in the stratosphere that's protection from UV, a wide range of things we don't know about it yet. And those are important enough that we wouldn't even be close to arguing for deployment until we learn a lot more. And I love for you both to weigh in on this one because this is really interesting it ties into just what we were just talking about which is that solar geo engineering could actually be a, what's I'm called a mitigation deterrent sort of takes the pressure off. Al Gore, certainly known for his, his role and advocacy to confront climate change at a recent Nobel summit, organized by the National Academy of Sciences said, we should reject any notion of funding efforts in his words to block the sun's rays from reaching the earth by making our blue skies white and taking away our possibilities to see the sky, the stars. We have the solutions we need he said, and we're gaining the political will to implement them in time. How do you square that to thinking about a research agenda around the Hail Mary pass. Well, no go ahead, Marcia. Well, I would just say, we, we hope that Al Gore is correct, and that there is now the political will, and that nations are around the globe will rise up to, you know, mend their wicked ways in terms of CO2 emissions. But right now, it's just the trajectory we're on is too little, and it's too late. I, it, there's still time, there's still time, but it's going to require redoubling the efforts. I just wanted to, Al Gore and the elevator with that comment in mind, what would you tell him, you know, as much as I respect Vice President Gore, I think his interpretation of what you might get from a research program is fundamentally incorrect. We wouldn't be well designed research. This wouldn't make blue skies white. A well defined research program could tell us whether or not this is a technology that we don't want to pursue, if that's what the science says, or a technology that we might want to pursue. And I think the, the preconception that that course statement comes from is the idea that that all research is is just step one toward deployment and it's going to be inexorably followed by step two. So what we need is the research, research about the human dimensions, the chemical dimensions, the ecosystem dimensions that tell us whether or not this is, is worth pursuing. And, and I think at this point it's a totally open case and what we might discover is that it's a bad idea, we shouldn't be pursuing it further and we should double down on mitigation. And thinking about the research we think about the questions that need to be asked and some of the questions that we can't yet answer. What do we know if anything about the effects that this might have on agriculture, you know, we have to grow our food around the world on extreme weather events as they're developing now on rain and monsoon rain patterns and different parts of the world. Do we know anything about this yet. There's been some modeling done, but models are only as good as the data that are input into them. And this is another reason why we need to do research to understand those impacts. And I would say, I'd also say to go or that we could well decide that we never want to do geo engineering. It doesn't mean that someone else couldn't do it to us. And it would be best to know ahead of time, what we would be dealing with, and how to determine who did it, and what impacts to attribute to them. Let's, you know, we're into this huge drought in California right now. Let's suppose that Saudi Arabia decided it was too warm there. We put up a blanket of aerosols in the stratosphere to reduce incoming sunlight and our drought deepens in California. Can we accuse the Saudis of having done that to us. You just made this a national security issue. It is. It is. So, how do these questions these big unknowns get answered. What kind of research would we be talking about is this one year five years 100 years, how would we do this, you know, the whole trajectory of the exploration of any topic is really incremental. And I'll give it for a while figure out what we've answered what we haven't studied a little more. There've been about 2000 papers published on some aspect of solar geo engineering and they've almost all been based on computer models which have their strengths and have their weaknesses, and and laboratory studies. There's a lot more to be done with computer and laboratory based research and, and the 2021 report advocates for doing whatever experiments that can be done in the laboratory in the laboratory. But there may be other experiments that we need to do in the field with releases of small quantities of materials of the atmosphere. There are some limited area studies that are already going on in the lower parts of the atmosphere. And, and I see the trajectory moving forward is very much learn a few things reconsider go back to the drawing board, share with the public, figure out what the next step is, and move forward. The consequences of a substantial increase in research activity here is that there's a really good chance we could say whether or not this is worth pursuing further with a few years of dedicated research. Let me let me ask you both about something else. I mentioned COVID earlier, you know all the bitter hecrimony that we've heard around something that is right in front of us right it's not often the distance. Not the climate change is often the distance anymore but it's, you know, less tangible certainly than your aunt or your mother your brother your kid getting sick. How would you get the consensus to pursue a research agenda like this and not get bludgeoned in the process or you know what. And do you even think about that in your in both of your reports Chris. You know, I already mentioned the concept of social feasibility. And what we've seen, even with small scale experiments that have been proposed in recent years is that there's a lot of public resistance. And there's a lot of indication that that even moving forward with research is going to generate a lot of public concern. And, and we need to understand how to address those concerns. And how to bring the public into the conversation so that the issue of the disruptiveness of the equity between different regions of the equity between different people and different financial groups gets gets addressed upfront. Otherwise, it's very likely that the agenda wouldn't be able to move forward even if it was technically a good idea. Marcia is president of the National Center of Sciences you think about this as among other things a lot. How would you, how do you think we engage the public in this way. Well, you know, I think the pandemic is a very good example. The pandemic is not something we wished upon ourselves. Right. But when it happened, we learned an awful lot. We learned an awful lot about how people respond to mitigation and prevention approaches such as mooring masks and vaccination. And I think that one under appreciated possibility is that we're going to have another volcanic eruption. We're definitely going to have another one, whether it's the size of penitubo I don't know, but we need to be prepared to deploy all observing the impacts of these events in our arsenal to understand exactly what the impacts are globally of another eruption like penitubo, because again, we haven't, we haven't caused it, but it has happened to us, and we are obliged to learn all we can from it. Let me ask you both a series of pretty quick questions to get through some of the other, what I think of pressure points and all of this. First of all, who would call the shots on something like this, both the calling shots on the research agenda and calling the shots in the actual deployment if it would happen, or something like this first you want to go first on that. The research agenda. It's important that a lot of the enabling is going to come from the perception that there is a fair and open discussion about it. The way the US is typically engaged in international research efforts is more a coalition of the willing model than it is kind of a top down structuring and, and the committee felt that that a practical way to approach it was to start some activities in the United States to have a warm welcome to input from the scientific communities and the broader publics around the world, and to try and have an iterative process by which we build up a coordinated program, but based on volunteer projects rather than in some kind of a hierarchical top down system for deployment. The, there really are profound questions that have not yet been answered about what kind of governance structures could be effective. That's part of the research agenda is to test drive concepts about what might work and what might not. At that point, Mark, Marcia, let me follow up so I hear from students all the time we know that a gigantic issue now is environmental justice and equity. Is it ethical for industrialized countries, which is where the support and presumably that most of the funding from this sort of thing would come from to propose it to pursue it to own this for even the three of us to be sitting around talking about it coming from the institutions we are sort of this elite bubble that we live in. So, let me let me put it this way Frank. I think that the countries that have been most responsible for the current pickle that we're in do have a responsibility to do everything they can to mitigate their current behavior. And also to ensure that they have explored all possible solutions because it actually is some of the countries that have contributed the least to global warming that are at most risk. So, so I think that that we have an obligation to make sure that we understand all the options that are on the table and include all of those other stakeholders in deciding before anything would be done. How would you include all those other stakeholders before. What do you mean by that. Okay, so there are two different concepts here. One is the governance on research. And the other is the governance on actual deployment. So, if you're talking about the governance of actual deployment. You have to go to international bodies such as the UN and places like that, in order to truly engage the nations that would be impacted by it. And in a situation like that, the science can inform what likely impacts are, but let's face it, even as is the case with global warming. There are winners and there are losers in in the whole concept. And so coming up with a fair method to determine how winners can reimburse losers, some sort of global insurance plan. I think would have to be part of any governance. Chris, I think of something like the Montreal protocols right which really brought science to policy to sort of global decision making and action. But is there anything that comes close to the scale that would be required pulling something like this together for solar geo engineering. And one of the things that the committee looked at carefully was with other complicated issues associated with genetic engineering or with other technologies are their examples of legal regimes out there that can be used to help govern the research. Notice that there are some parallels. There are some laws in the US that are that are relevant and might be helpful. But there are a lot of areas where solar geo engineering is just so different that we need to be looking at whole new kinds of governance structures and part of the research agenda moving forward is to is to figure out what kinds of governments might be relevant. And also what kind might be practical because one of the things we've seen in recent years is that, you know, it's not like the, you know, a few rich countries get together and say, this is the way we're going to go forward and, and, and come up with a with an international treaty regime that everybody buys into. This is going to have to be an effort that has buy in for around the world from rich countries from poor countries, and really represents a new kind of governance entity that we really haven't deployed and haven't figured out how to deploy. You know, it strikes me to that it requires something else. I, you know, I'm full disclosure, I'm on the affiliated with the Global Council for Science and the environment, which is all about trying to bring science into policymaking. And we would need to make incredible strides in helping people and decision makers leaders understand that science is fundamental to the policymaking the decisions they're making despite the politics around them to get to a place like this. And you both talk a little bit about the research itself because you both spoke about moving forward and that's what we'll start doing will aim our, our gaze on moving forward here. Play out the debate a bit if you would because there are some who support the research and others who are adamantly opposed to to even going into the research. Marsha you want to lead off with that and then Chris because I know that was a big part of your work in the report. Sure. So, some forms of solar geo engineering are actually rather local in how they behave. One example is cloud brightening, where you actually make a low level clouds that appear for example here along the California coast, you make them brighter, so that they actually just reflect more back into space. How do you do that and is that is that a feasible thing that could actually be done. Yeah, you spray seawater on them. And they become more reflective. So that's the sort of research that could be done without having any huge long lasting global impacts to see how much difference does it make. And is it safe. Are there unintended consequences. Another that has been proposed is to thin clouds that form in high latitudes. So I grew up in Minnesota. And I can tell you for sure that the coldest days in the winter were the days where there was no cloud cover, because basically all the heat just goes back up in the space. So one thing that's been proposed, given the exceptional warming that is happening at in the polar regions is to thin clouds there in order to allow more heat to escape. And that tool is a viable credible thing that could be done that that could be done in an experimental approach. And it would have local impacts for a short period of time one could you know measure how much extra heat is escaping from the polar regions, and see whether it would be worth doing and again what the unintended consequences are. Before I speak to specifics of research, let me emphasize the two key concerns that have made people critical of pursuing research are the thing we've already talked about mitigation deterrence would would simply being involved in researching would make us less likely to decrease emissions greenhouse gases. And what you might call a slippery slope that once you start doing research you build a group of people who are kind of committed to the technology and you start getting corporations who are building the infrastructure and want to keep building it in that that step one always leads to step two. So it's, it's important in thinking about the research agenda to say, how would we design a research program that from the very start was conscious and addressing the programs and mitigation deterrence and slippery slope. So some of the experiments you want to do or and in the physical domain there. There's a lot of things about looking at the way particles dispersed in the atmosphere. In some cases using what you might call experiments of opportunity when a volcano goes off or looking at at the, the plume that forms and clouds behind a ship that's going across But in other cases what you really want to focus on is how, how do people perceive these technologies, what kinds of information make people more or less comfortable with making decisions, and what kind of structures might be appropriate. I would also emphasize that when I look at this really, really complicated landscape of everything we need to know in order to have a sense of whether solar geoengineering might be helpful. There are about half of them are in this physical space and the unintended consequences, and about half are in the social space so we want to make sure that that we think about the research program is integrated across both the social and the physical You mentioned the slippery slope component here. And how much of that has has factored into the pushback against against proceed proceeding with the research. It's a legitimate concern there are lots of cases in which even doing research builds up contingency of individuals and firms and institutions who have a lot invested in the research moving forward and in some cases in deployment. So you really need to be thoughtful about that one of the things that we put a lot of effort in in the 2021 report is, is talking about what exit ramps from the research might be and how research programs would be redirected or terminated. If the evidence indicates that you know this particular stream is not useful. Tell us about the exit ramp how would the exit ramp actually be taken and under what circumstance. Well, I mean a way to think about it in the research domain is that research activity, or a suite of research activities could be funded. And rather than saying okay, at the end of this we're going to refund the next tranche that would be an evaluation that said, should this be funded should it be redirected. And that process needs to not just be directed from within side the scientific community, but it needs to be we talked about it as braiding in the governance structures and public engagement so that there's an ability to listen to voices from across the geographic and political spectrum with all this that we've discussed and has background and backdrop. Let's talk a little bit about moving toward what would be perceived and pursued as a responsible research agenda married we hope to responsible policy. Marsha, you know, we've seen the United States kind of have a seesaw approach to climate change in and out of the Paris Accords. The role in global agreements. Would we with the United States and American scientists have legitimacy to propose and lead something like this. Well, I think that's one reason why we've recommended that this be internationally pursued that this not be come across as American imperialism in looking at solutions. And if I can just add to what Chris just said, we already have seen the pushback on mitigation of co2 release from the fossil fuel industry. And what we don't want to create is yet another industry that benefits from solar geo engineering. And we've replaced one special interest group with another. That is not necessarily acting in the public's best interest, but rather in its own profit best interest. But I think that, yes, I do think that there is not enough consistency in will here in the United States for for the United States to necessarily go this alone and show the rest of the world what needs to be done. Okay, so if that's the case and I think you're right. There's no question about that. It's going to be fraud in the best of circumstances, but especially now. How then does this become a fully international issue and Marsha since you lead the US National Academy of Sciences, what about the national academies and academies in other countries, the developing world. How can this be made, you know, kind of fully internationalism speak and then Chris jump in chime in on this. So I think that when it comes to research that the national academies and there are several international bodies within which the national academies all get together and discuss important issues. And I think those could be for for discussing the research agenda. And even coming up with potential governance structures and other things that would give scientists confidence that these exit ramps were being used, and that there was international buy in on what's happening. I think when it comes to going beyond research. As Chris has said, this has to involve civil society. It cannot be a discussion among scientists. One thing I add about building an international research program is that we have a pretty good record of building international programs by invitation, creating a welcoming environment. And one of the things we discussed a lot in the 2021 committee was providing us based funding to encourage participation by especially scientists from developing countries. And I think the invitation to make it international really needs to be wholehearted and it needs to be warm. Part of the reason that the program needs to be international is that, as you've said Frank it's not going to be successful if it's perceived as a as a US siloed effort, and we need to understand that as as we think about, you know, making this invitation to participate from a national perspective, genuinely wholehearted. So could I ask you about who's the we here. Like, who's the, who's the lead advocate for this who's bringing this together and and drive and driving the process here. The national community, you know, the scientific community is remarkably self organizing. There are institutions like the National Academy of Sciences that that play a wonderful role as a convening entity. But but it's the sense within the scientific community of what's important. What are the avenues that can be pursued in order to generate the increments in activity and and the invitations that can go internationally. And you know that the National Academies are can play a key role, the federal government can play a key role in in making funding available through some of the global change research programs in the in the federal government and individuals can also play a key role in working with colleagues around the world. I want to ask you some particulars of the research and the science for a moment how would the science and the research help inform some really tough questions. What kinds of technologies technologies to use, where exactly to deploy them. What the goals, the end goals might be where to stop where those off ramps might be Chris. The trade offs. Okay, what kinds of trade offs are accepted. I mean, there are a lot of really gnarly questions here. Well, so I think that this goes back to what Chris said about the fact that the science can tell you what might happen and what is likely to happen, but it can't tell you whether therefore this is better than other options. But right now, we don't even know if solar engine geo engineering is better than other options and better for who in what way. So, this is why I go back to this idea that there would need to be some very transparent view view that would emerge from the science of what the impacts are where for how long. And therefore, I'm allowing then civil society to way. If this is in the best interest of 70% of the globe. How does that 70% indemnify losses to the other 30% such that everyone agrees that this is a good thing to do. Because if it's only the 70% saying it's a good thing to do and they do nothing to help the other 30% then this is just a non starter. Chris give us, you know, an example of one of these trade offs that people would have to confront and deal with and science and research has to illuminate. Well, I think the whole area of unintended unintended consequences is is going to be especially challenging here. So, I think we've actually already spoke to the example of what if there's an intensification of the California drought and California scientists think that that's probably a result of a of a geo engineering intervention. How about it, do you do file a case in the court of geo engineering resolution. Is there an automatic pool of funds that are set aside. These are all super difficult questions where scholarship can play an important role in helping set up structures and I think that the answer to your question is how you would deal with these complicated societal issues is that those have to be pursued through a dialogue between research and civil society to figure out something that's going to be practical. And in today's world and with an issue was complicated as geo engineering. It's going to be a very challenging conversation. If I could add one thing to what Chris just said. This whole issue of unintended consequences and which are actually consequences of some kind of intervention is a big part of climate research right now, because we are trying to understand through basic climate research, how much of hurricane activity, a number of major hurricanes went through the Gulf of Mexico last year. How much of the drought in California, etc. How much of this can actually be attributed to climate change. So everything that we are doing right now to better understand climate attribution is actually essential understanding to then be able to also attribute weather events, long term changes to an intervention. To that point in Chris in the 2020 report, one of the things that struck me was where it said our scientific understanding of the solar geo engineering technologies is very limited in areas of how they might affect weather agriculture or agriculture or natural ecosystems are human health are you know our human health is part of this. We started out by talking about how the impacts of climate change are serious and getting more serious and how we need to understand what the portfolio possible solutions might look like. And even though there are some indications that these solar geo engineering ideas might be useful we don't know anywhere close to enough to say that we ought to include them in the portfolio the kinds of uncertainties that you highlight about extreme events about climate agriculture or impacts on health. Those are exactly the kinds of things that we, we desperately need more information about before we could even decide whether or not this is something that deserves more investment or more consideration. So the 2021 report says that in some cases outdoor experiments might be permissible, you know, for under certain circumstances. You've talked about rogue actors and nations and you could have people developing technologies deploying them, you know, kind of, then what. So, how do we wrap our brain around how social geo engineering research compares to research and other areas of emerging technologies that have global implications biotechnology is one for example that comes to mind. Exactly. So, I think with engineering life through gene editing and other things like this, scientists are working very hard right now to establish rules of the road, and to police them. We saw how the scientific community came down very hard on a Chinese scientist who edited the embryos of twin girls. And it's the same thing. I see it happening right now in research on solar geo engineering, where people who are viewed as coloring outside of the lines are being soundly criticized by the research community for doing that. I think that we've had enough of an opportunity to get our act together on this, simply because there has been so little research funding going into this so far that it just hasn't really been an issue, unlike editing life. But I think in the same way, we'll need to do that. And we're almost out of time here. One more kind of question point and I'm going to ask you to pull what we've talked about here together a little bit. We're heading to top 21 in November. What about social geo engineering and research governing, plugging into things like Paris Accord, the Kigali amendments Montreal protocol I mentioned earlier but these kind of global agreements that have some press. But the Paris agreement doesn't explicitly say anything except about what the temperature goal should be. And one possibility is that using solar geo engineering as one of many approaches to help reach the temperature goal is it is something that should be a part of the conversation. Far from being clear enough that we should even be headed in that direction. At this point, I think we just need to know whether or not to include it in the conversation and whether to try to learn more. Marsha you get the last word. Well, the one thing I will say is that any prospects of solar geo engineering need to be closely linked in treaties in plans and programs with reduction of CO2 emissions, because it is just a bandaid. Any intervention last a year or two and then has to be repeated. And we don't want to have to repeat this for eternity. So unless it is strongly linked to some kind of mitigation of CO2 release. It's an on starter. So at this conversation has really highlighted is the immense complexity of all of this complexity of the science and getting to a research agenda governance around a research agenda of engaging civil society the general public, as well as national leaders, academic leaders and frankly, those in the public sphere in the media who are going to need to slow down a little bit to explain and to engage something that is immensely complicated and controversial and build with what science is all about in so many ways which is uncertainty. We're very bad at embracing uncertainty in public life we need to get better at that so thank you both for this incredible conversation and for everything you've done I've certainly learned a lot. And I see Alex is back and I'm going to say thanks and Alex I'll turn it over to you. Thanks Frank, and thank you all for joining the National Academies of Sciences, Engineering and Medicine for our fourth climate conversation. I want to thank Marsha and Chris for sharing your incredible perspectives and background on this topic, and to give a special thanks to Frank for your excellent moderation and your your wrap up. The conversation was recorded and should be available for viewing on this same web page starting tomorrow. There's a link above to register for the June 17 climate conversation which you can access by going to infrastructure dot event bright calm. At that event will talk about the role of infrastructure and engineering just of the normal type in building a resilient future. We'll also share this information through our climate at the National Academies newsletter, which you can also sign up for above. As a final reminder to share your feedback on today's event or ideas for future events, please see the survey linked above. And I just want to say thank you all for joining us today and again thanks to Frank, Marsha and Chris for sharing their expertise and time with us. Thank you to everyone, the climate communications team at the National Academies and to everyone behind the scenes who supported today's events. We're really honored to continue the conversation through events like this, and we hope you all stay safe and have a great day. Thanks so much.