In this week’s episode, host Kristin Hayes talks with Tyler Felgenhauer, a research director and senior research scientist at Duke University, about social science issues that are associated with solar geoengineering. Felgenhauer discusses different technologies that can facilitate solar geoengineering, the risks and benefits of these technologies, how international cooperation could affect the deployment of solar geoengineering, and recent social science research on solar geoengineering. Attend the upcoming “Solar Geoengineering Futures” conference on September 28 and 29 at Resources for the Future to join the ongoing discussion around solar geoengineering.
Listen to the Podcast
- Solar geoengineering isn’t a replacement for reducing emissions: “It could be tempting to lower our emissions-mitigation goals in favor of just relying on solar geoengineering. That would be a mistake, because the only way to solve climate change in the long term is to lower our emissions to net zero and below.” (8:15)
- International cooperation would be crucial to the deployment of solar geoengineering: “It’s so cheap and relatively straightforward to embark on this technology that many countries may be incentivized to go ahead. Related to that is a problem of wanting to avoid a situation where multiple countries are engaging in sort of a patchwork quilt of different geoengineering interventions with no coordination. It is really imperative that if this technology were ever used globally, it needs to be done in a cooperative way so as not to cause international strife.” (13:06)
- Solar geoengineering poses risks and possible benefits: “Solar geoengineering creates a health-hazard risk from new particulates, changes in ozone, and changes in ultraviolet exposure. However, it also creates a huge benefit in terms of avoided mortality due to lowered frequency and intensity of heat waves. [Harding et al.] find that the benefit from heat mortality is 10 or even 100 times greater than the risks of solar geoengineering. That’s just one example of a larger risk assessment that needs to be done for geoengineering.” (18:15)
Top of the Stack
- “Solar Geoengineering Futures: Interdisciplinary Research to Inform Decisionmaking” event on September 28 and 29, hosted by Resources for the Future
- Solar geoengineering research at Resources for the Future
- “Social Science Research to Inform Solar Geoengineering” by Joseph E. Aldy, Tyler Felgenhauer, William A. Pizer, Massimo Tavoni, Mariia Belaia, Mark E. Borsuk, Arunabha Ghosh, Garth Heutel, Daniel Heyen, Joshua Horton, David Keith, Christine Merk, Juan Moreno-Cruz, Jesse L. Reynolds, Katharine Ricke, Wilfried Rickels, Soheil Shayegh, Wake Smith, Simone Tilmes, Gernot Wagner, and Jonathan B. Wiener
- The Uninhabitable Earth by David Wallace-Wells
- Climate Change and the Nation State by Anatol Lieven
The Full Transcript
Kristin Hayes: Hello and welcome to Resources Radio, a weekly podcast from Resources for the Future. I'm your host, Kristin Hayes. My guest today is Tyler Felgenhauer, research director at the Duke Center on Risk and a senior research scientist with the Modeling Environmental Risks and Decisions Group at Duke University. A big chunk of Tyler's current work involves investigating how to compare the risks and possible benefits of solar geoengineering with the risks of climate change in future scenarios. He's worked closely with researchers here at Resources for the Future (RFF) on that topic.
Today, Tyler and I are going to be talking about a new set of papers recently released under the auspices of RFF'S Solar Geoengineering Project. These papers were commissioned and funded by the project team and are designed to really expand the knowledge base around a range of social science issues connected to solar geoengineering. Stay with us.
Hi, Tyler. It's great to talk with you today.
Tyler Felgenhauer: Hi, Kristin. Thanks for having me.
Kristin Hayes: Of course. Well, I have known you for a couple of years now, but I'm still very excited to hear the answer to my opening get-to-know you question all the same. Why don't you tell our listeners just a bit about your background and how you came to work on risk issues?
Tyler Felgenhauer: Climate change has been a long-time interest of mine, but I actually started out in my career working out on a completely different topic: international security and international political development issues both in the United States and abroad. When 9/11 happened, I had the opposite reaction of many people. Many people, when 9/11 happened, moved into the security field, and I actually decided to take the opportunity to change my career and work more on environmental security and then primarily climate change issues.
When I did my graduate work at University of North Carolina, I was looking primarily from a policy perspective at how a policymaker might approach climate change from a risk-management perspective—how they might allocate resources to lowering our emissions as one way to reduce risk, versus spending money on adaptation as another way to reduce risk. And I had always had in the back of my mind this awareness of this third new set of technologies, which was very interesting and also a little bit scary, called “geoengineering,” and it made sense to start to incorporate geoengineering into this overall policy mix. I started looking at that after my graduate work when I was at the US Environmental Protection Agency, and now I'm happily here at Duke here with the Duke Center on Risk.
Kristin Hayes: Fantastic. Well, that was a very concise and comprehensive lead-in to our discussion around solar geoengineering and this question of comparative risks and possible benefits, when you think about solar geoengineering versus the risks of climate change. But before we get into the deep on the risk side, I wonder if you can remind our listeners what solar geoengineering means. I know there are a number of terms that get tossed around that have similar meaning. Maybe say just what some of the possible risks and benefits are?
Tyler Felgenhauer: I'd be happy to. It's known by a number of terms. Geoengineering in general is also known as “climate intervention” or “solar radiation management." I guess I'll be using the term “solar radiation modification” (SRM) here today. And it's really an umbrella term for a family of approaches that would use different methods to reflect a portion of incoming sunlight from the earth in order to slow the warming that we're experiencing now, or even to cool the Earth. And so the most-studied method—none of these have been tried yet—is called “stratospheric aerosol injection,” which would involve a fleet of planes flying to the stratosphere about twice as high as a modern commercial jet, regularly dumping loads of sulfates, which are highly reflective particles, into the stratosphere. This would spread throughout the world and reflect a slight amount of incoming sunlight and help cool the earth.
The idea is to mimic naturally occurring volcanoes, such as the eruption of Mount Pinatubo in 1991, which also emitted a large amount of sulfates to the stratosphere and cooled the earth for about a year. That's the most-studied approach. Other approaches include something called “marine cloud brightening,” which would involve encouraging the formation of low-lying, large marine clouds to reflect sunlight. There are other approaches that are being explored, such as anything to do with what's called land- or sea-based albedo modification, which is basically increasing the reflectivity of surfaces. Then, in the future, we might even think of more science fiction–oriented approaches based in space.
From a risk–trade-off perspective, I could just briefly go into the possible risks and benefits of stratospheric aerosol injection in particular. I approach it from a policy perspective, where we're trying to reduce the risks of climate change. That's the only reason we're talking about the stratospheric aerosol injection. Again, we all know those risks: the droughts, forest fires, heat waves, stronger hurricanes, increased sea level rise. The potential benefits of SRM would be profound in this area. It would come from cooling, where using this method to slightly reflect some of the sunlight coming in could have profound benefits, in terms of alleviating a lot of those risks: extreme temperature events, heat waves, extreme precipitation events, slowing the melting of ice on land, and slowing sea level rise. Those benefits are well known, and they would come in the form of a reduced increase in temperature. There could also be some cobenefits of SRM, which are actually too small to be considered, but, just for reasons of being comprehensive, we look at those, as well.
On the flip side are the risks. SRM is risky, and it's never been tried before. The primary risk is that even though we’re fairly confident that hypothetical geoengineering deployment could slow temperature rise or even cool the planet, it doesn't act so uniformly, in terms of precipitation effects. So, while the temperature globally could fall, and those benefits would be realized, precipitation outcomes could be different for different regions of the world, and some of those could be damaging. That's the primary climatic risk.
There's another set of risks that we also look at, which we call the countervailing risks, which are less related to climate change and more what we might think of these as side effects. The first set of side effects would be biophysical. SRM in the form of stratospheric aerosol injection might result in increased acid deposition in pristine areas of the world, because you're emitting all these particles to the stratosphere, which spread globally. It could slow the recovery of the ozone that we're trying to have recover, and it could also result in light diffusion and dimming, which could affect crop yields. All of those effects are still being studied.
The risks that I look at are the social side effects, and these might include the potential for international conflict, where countries are in a disagreement over how the geoengineering is done or even what the global thermostat is set at. Another big risk socially is that, because geoengineering is so relatively cheap and also relatively effective, it has high leverage in the climate. It could be tempting to lower our emissions-mitigation goals in favor of just relying on solar geoengineering. That would be a mistake, because the only way to solve climate change in the long term is to lower our emissions to net zero and below.
Related to that is a risk that we could become dependent on it, and if we become dependent on this technology, there's a risk, if it ever should stop, something called a “termination shock” would happen, where temperatures would go back to where they were had we not done geoengineering in the first place. In our research, we look at this complete picture of all the benefits of solar geoengineering paired with all the risks of solar geoengineering.
Kristin Hayes: Thank you for that detail. I do think that you've laid out a number of the physical science questions and unknowns and also referenced some of the social science questions and unknowns, which is actually the focus of our conversation today, which is great. We've had a few conversations about solar geoengineering here on Resources Radio, but I'm very grateful for the chance to talk about this intersection of SRM and social science research in particular. Maybe I can ask you just to give us a little bit more context about why you and your coleads in this work have really focused on that particular intersection in recent years.
Tyler Felgenhauer: In this work, I am really motivated by a report that came out almost 15 years ago from the UK's Royal Society, which is the equivalent to the National Academy of Sciences. In that report, they stated, in effect, that despite all of the questions surrounding the climatic effects of solar geoengineering, as well as the engineering challenges, they concluded that, "the acceptability of geoengineering will be determined as much by societal, legal, and political issues as by the scientific and technical factors." That really motivates me, because I go to both types of conferences. Where it's primarily natural scientists, the question always arises, "Well, how would this ever be managed?" Then, on the flip side, you go to a conference with primarily social scientists, and the question is, "Well, are we understanding this technology correctly?" Both sides need to cooperate, but I'm exclusively working on the social science questions related to geoengineering.
In terms of our motivation with the RFF project, I see three large sets of social science questions that really, in my mind, should receive priority over the next decade. First, could SRM be done in a way that avoids what's called the “moral hazard risk,” which I alluded to earlier and is this idea that we lower our motivation to continue mitigating down to net zero and below, because geoengineering is so effective and relatively cheap compared to mitigation. If we ever decided to deploy geoengineering, could we do it in a way that also increases our mitigation efforts, knowing that that's the only way to solve climate change in the long term? Moral hazard risk is a huge question that's outstanding that people are working on right now.
The second large social science question is, Could solar geoengineering be done in a way that's fair? By that, I mean it doesn't cause significant harm to particular regions of the world. If there is harm done to regions of the world, can we help those areas become whole again? Or are there mechanisms for compensation? Are there mechanisms for decisionmaking on that? In other words, you can imagine a group of representatives for the globe that asks, "Knowing that this might help climate change, but there's also this smaller risk that it could result in damaging precipitation effects for your particular region, would you still sign on to it?" That gets into the governance question of how to make decisions on geoengineering in a democratic and representative way. Decisions both to deploy if we ever came to that point, and also decisions on when to stop or decisions on how to alter the program, as needed.
Finally, a large social science research question that’s related to this is, Could it ever be deployed cooperatively in a way that doesn't result in international conflict? We really want to avoid two bad outcomes that people are researching. One is a unilateral deployment by some single country that affects the climate for the entire globe. It's motivated by what's called the “free driver incentive,” where, again, it's so cheap and relatively straightforward to embark on this technology that many countries may be incentivized to go ahead. Related to that is a problem of wanting to avoid a situation where multiple countries are engaging in sort of a patchwork quilt of different geoengineering interventions with no coordination. It is really imperative that if this technology were ever used globally, it needs to be done in a cooperative way not to cause international strife.
Kristin Hayes: Right, right. You have done a fantastic job once again laying out what that social science research agenda should cover. I appreciate that. I guess I wanted to give you an opportunity to speak a little bit about how you and your colleagues have actually been working to drive that research agenda forward in this space. Can you say a little bit more about the work that you've been doing to work towards answers to some of those critical questions?
Tyler Felgenhauer: Yeah. The project began with Resources for the Future in 2020. And Kristin, you were a vital part of that early work with what was called the SRM Transatlantic Dialogue, where we had a series of meetings during COVID among experts both in North America and Europe to try to develop a set of social science research questions to address for solar geoengineering. That effort resulted in an article in Science, which I would encourage your readers to take a look at (and I think it'll be posted with the podcast) that really outlined our conclusions and a set of goals for social science research going forward. We hope that contributed to—side note—this recent report from the White House Office of Science and Technology Policy, which also set forth a set of social science research questions, as well as natural science questions that could be addressed with a research program. The project continues, and the goals of the project are basically to better understand the risks, the potential benefits, and the societal implications of this technology as a possible approach to help reduce risk, alongside more aggressive mitigation and necessary adaptation.
The next step in this was to issue a competitive solicitation for sponsored research to look at some of the questions that we raised. We really wanted to get a wide variety of submissions, and we received 20 outstanding applications from all over the globe with researchers from 14 countries and from 6 countries in the Global South and representing a wide variety of social science fields. We received applications from the fields of economics, political science, behavioral science, science policy, and different methods ranging from integrated assessment and game-theoretic modeling, survey administration, to conceptual and mental modeling. We were happy to choose the best eight submissions of those. Now, after a couple of other workshops, we're happy to have released the final set of eight working papers, which are now in the process of being published in scientific journals.
Kristin Hayes: That is fantastic. I will also note that the working version of those eight papers are all available on the RFF website. I will encourage folks to take a look at those. But maybe you can talk in just a little bit more detail about those eight papers funded via the RFF Solar Geoengineering Project. I know that's a lot to cover. There's a lot of depth in those eight papers. Maybe just share some of the themes about the papers—maybe a highlight, one or two examples of findings—but really hearing about those themes would be fantastic.
Tyler Felgenhauer: Happy to summarize some of the themes. The eight papers really are great in pushing our understanding of the social science around geoengineering, pushing that forward. In a broad sense, the themes are familiar, but the papers really provide a set of supporting perspectives. In reading the eight final papers, three themes emerged. The first is that SRM could be a profoundly beneficial part of an overall climate change policy portfolio. Again, that also includes mitigation, carbon dioxide removal, adaptation. We really need to look at the benefits of geoengineering and the risks and the risk–trade-off framework.
I'd refer the listeners to one example from a paper led by Anthony Harding and also with David Keith, Wenchang Yang, and Gabriel Vecchi. They looked at the mortality risks and benefits—so, the impact of solar geoengineering on temperature-attributable mortality. What they find is that solar geoengineering creates a health-hazard risk from new particulates, changes in ozone, changes in ultraviolet exposure. However, it also creates a huge benefit in terms of avoided mortality due to lowered frequency and intensity of heat waves. They find that that benefit from heat mortality is 10, possibly even 100, times greater than the risks of that geoengineering. That's just one example of a larger risk assessment that needs to be done for geoengineering.
A second theme from the papers, and it comes out in several of the works, is that any deployment or research into SRM will be strongly influenced by societal, political, and personal attitudes on risk. How do you view risk of a new technology versus risk in climate change? It could be determined by trust in this new emerging technology—Do you tend to trust the new technology and how it's managed?—and then your preferred level of cooling and your views on how it might play out.
We've got a couple of papers looking at the mental modeling and the risk perception surrounding geoengineering of those led by Dale Rothman and also by Brian Beckage. Then, we also have a couple of papers led by researchers from the Global South—those by Govindasamy Bala and also Athar Hussain who, in the latter two, surveyed both researchers and larger groups of people on their attitudes on solar geoengineering.
A lot of the survey results from their papers show that there's actually a fairly strong openness to geoengineering, and it contributes to this larger set of literature that might explore this idea that it might be—it's not certain, we don't know—but it might be the case that the Global South might be more amenable to geoengineering approaches, especially because of the fact that the Global South is more vulnerable to climate change.
Then, a final theme from the papers is that how geoengineering plays out will be influenced strongly by the perceptions and actions of others. Here, thinking of the primary actor being the nation-state. You can think of in terms of game-theoretic modeling, where, at first, countries are having a hard time cooperating in getting a global-mitigation regime—how can that cooperation be enhanced? Then, if there's this new technology of geoengineering, how does that affect the cooperation on mitigation?
Ideally, if geoengineering ever were to be deployed, you'd want to have stronger cooperation on mitigation and also cooperation on some sort of geoengineering. Papers led by Dave McEvoy look at that—how geoengineering would affect international environmental agreements. There's also the question of learning. How does an actor change its decisions when it learns how effective geoengineering is or is not? That's a really fascinating paper that Felix Meier and Christian Traeger developed, looking at uncertainty and learning for geoengineering's effectiveness. Then, finally, Juan Moreno-Cruz and also Anthony Harding looked at how countries might use international diplomatic methods to coerce or encourage other countries to join their point of view on geoengineering versus mitigation.
There's a lot of strategic behavior that's going to be occurring. It goes back to the main question of, How could this be done cooperatively, and how could this be done in a way that does not dissuade us from mitigating even more than we're now?
Kristin Hayes: That is a fascinating set of topics. And I will say, as you were describing particularly that last section on cooperative approaches—I'm an optimist by nature, but in this case, I'm thinking back to the number of times that we've tried cooperative approaches related to climate change before, and they're fraught. They're not straightforward, and it seems like it's very halting, slow progress. So, I can imagine that that cornerstone of trust and building trust in the technology, building trust in the organizations that are governing the management of that technology, is a really critical piece of the puzzle. Those are some great insights about how all of these pieces need to fit together.
Maybe just one other social science question that I wanted to ask you about. Some of our listeners may recall that we actually aired an episode a few weeks ago here on Resources Radio with Dr. Shuchi Talati, and that was really focused on how to ensure inclusion of multiple stakeholder voices in any of these very complex decisionmaking processes related to solar geoengineering. I guess I just wanted to ask how you think about that in relation to the work that you all have been funding?
Tyler Felgenhauer: It is a crucial question, and I really applaud Shuchi's work in that area, developing global capacity for addressing these issues. There's also the work of the Degrees Modeling Fund run by Andy Parker, who's been working for a long time on getting researchers from the Global South involved in studying geoengineering and involved in these international conferences. Climate change is a global problem, obviously, and it'll require a range of voices, especially on geoengineering, if we're ever to discuss the possibility of using this technology. Again, I would go back to the—I guess it's a Rawlsian approach—would a representative country sign on to some SRM deployment knowing the risks? We want to have a situation where most countries of the world would be signing on to this knowing that the work has been done, that they've been involved in the process, that they have a voice in the decisionmaking around it.
Finally, there's been a lot of work done from a group called the Carnegie Climate Governance Initiative, which has been trying to get this issue on the international diplomatic agenda at the UN and then eventually at the conference of parties to the United Nations Framework Convention on Climate Change. That's the first step, really. That's a key step that I see—that we need to get this issue onto international agendas so that people start really acknowledging that we need to start talking about this now before we surpass 1.5°C of warming.
Kristin Hayes: That's a great highlight of one next step that I think you all have identified. Let's talk a little bit about the next steps, maybe particularly in the work of the solar geoengineering project or other related efforts you have around what needs to happen next when it comes to the social science research agenda or more broadly in terms of getting solar geoengineering into the international dialogue.
Tyler Felgenhauer: I'm really excited about an event that we're hosting with RFF at the end of September—September 28 and 29—and it's a public event in Washington, DC. I'd encourage your listeners to check out the link and to consider signing up in person or online. It's a public-facing synopsis of social science research as it stands now, and we're hoping to get an audience of a lot of people who work on climate change but maybe are new to geoengineering, or Washington, DC–based policymakers and environmental-NGO advocates who've been spending their lives on climate change and really may have questions about geoengineering.
Over a series of panels over a day and a half, we'll be covering some of these cutting-edge issues. We'll be looking at the benefits and risks—the moral hazard risks, specifically—possible optimal-deployment scenarios that economists or models might use, and then the more nonoptimal or possibly more politically realistic scenarios that political scientists or others might investigate. We'll have a panel on research capacity-building and then, finally, a panel on looking at a research agenda for the next 10 years. I think it'll be a great event in the month.
Kristin Hayes: Great overview for a lot of people. Lots to chew on in that one, I'm sure.
Tyler Felgenhauer: I'm involved in a few other projects, but I guess I'll just highlight a second one. It's one funded by the National Science Foundation and run with colleagues from the National Center for Atmospheric Research in Boulder, Colorado, along with fellow investigators from both Louisiana State University and Arizona State University. We're looking at how to model how different climate interventions (we're calling it a “climate intervention” that would include both solar geoengineering as well as carbon dioxide removal, but basically different interventions) might help us to either avoid 1.5°C or at least bring us back down to a world where we're closer to 1.5°C of warming. The interesting point is that a lot of these geoengineering proposals—people think they could happen fairly quickly and cheaply, and they could, but they still might take a decade or two or even longer to really ramp up. It just reminds us that, even if we do have these new possible approaches, they're not a solution to the problem of climate change, which is really, again, mitigating and lowering our emissions down to net zero and below.
Kristin Hayes: Well, Tyler, this has been fantastic. I really appreciate your introducing us to these new research papers and obviously giving us a lot of context about the intersection of social science with solar geoengineering, or with SRM. I encourage our listeners to check out the papers if they're so inclined and definitely check out that public event, which I do think is going to be a really nice synthesis of all the work that the team has been doing and that Tyler has been so critical in.
With that, let me close with our regular feature called Top of the Stack, and I'd love to ask you to recommend some good content for our listeners, it can be on this subject or can be more broad, but Tyler, what's on the top of your stack?
Tyler Felgenhauer: A couple of books came to mind, and oddly, they're not focused on geoengineering, but on climate change. The best book I've read in the past couple of years about climate change is one your listeners are probably familiar with, called The Uninhabitable Earth: Life After Warming by David Wallace-Wells. It came out a couple of years ago. It's just a great, highly readable overview of the plethora of climate change impacts and risks that we're set to face. The point I draw from it often is just that this 1.5°C international goal is somewhat politically determined, but the point made is that 1.4°C of warming will be a lot worse than 1.3°C, which is a lot worse than 1.2°C. It provides motivation for me, at least, for when we might eventually cross 1.5°C of warming, that we still have a fight on our hands—that it's still worth us to get to 1.6°C as opposed to 1.7°C. 1.7°C will be much better than 1.8° of warming—that really provides motivation on my end.
A second book recommendation—it's a little bit more specialized, and it comes back to my earlier career in international security—is called Climate Change and the Nation State: The Case for Nationalism in a Warming World by Anatol Lieven. He makes the argument that there's really no way to fully address climate change without a strong national level of leadership. It's a bit contrarian in that it goes against the political Right, which might be more resistant to state intervention in our economies, and it also goes against the political Left, which may prefer that civil society and political movements take the lead, both of which are crucial in this effort. But he makes a good case that it's still the nation-state that is making decisions on large-scale climate change, and it's still the true decisionmakers, at least at the UN level. Then, I'd encourage the listeners to look at the other links to our project, as well as the upcoming event.
Kristin Hayes: Great. Great. Well, thank you for those recommendations, and thank you again for talking to me.
Tyler Felgenhauer: Thank you for having me.
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