For Solar Geoengineering, Daunting Policy Questions Await

A climate economist discusses why efforts to cool earth’s climate through solar geoengineering appear all but inevitable, and considers the policy questions and political battles to come.

There is no overarching, national debate into the merits of solar geoengineering, which is process to artificially cool the Earth by reflecting sunlight back into space. The technology sounds fanciful, the stuff of science fiction. Yet earlier this year the National Academies of Sciences issued an urgent request to Washington to begin a federal research program into geoengineering. That request has, so far, largely fallen on deaf ears.

Climate economist Gernot Wagner believes solar geoengineering is inevitable despite the relative lack of attention the technology has attracted to date. In a recently published book he makes the case for this inevitability, and also presents a compelling argument for why much more research into geoengineering’s risks must be completed if is to be put into practice. In the podcast, he explores why solar geoengineering is fundamentally different from other strategies that address climate change, and why research programs into the technology must be tightly governed. He also discusses concern that solar geoengineering’s implementation, if inevitable, is likely to stoke fierce policy debate and, quite possibly, geopolitical tensions.

Gernot Wagner is a climate economist at New York University and author of the recently published book Geoengineering: the Gamble. He is also co-author of Climate Shock, which was chosen by the Financial Times as a best book in economics in 2015.

Andy Stone: Welcome to the Energy Policy Now podcast from the Kleinman Center for Energy Policy at the University of Pennsylvania. I’m Andy Stone.

The focus of today’s podcast is a technology that could very well play a critical role in the global effort to minimize the impact of climate change. Yet this technology remains something of a taboo, and if that’s too strong a word, I’ll simply point out that despite the promise it may hold, it has yet to make its way into mainstream dialogue among policy-makers or champions of green industry, here in the United States or pretty much anywhere else. There is no grand national debate into the merits of solar geoengineering, which is a process to artificially cool the Earth by reflecting sunlight back into space. The technology sounds fanciful — the stuff of science fiction. Yet earlier this year, the National Academies of Sciences issued an urgent request to Washington to begin a federal research program into geoengineering. That request has, so far, fallen on deaf ears.

Today’s guest is someone who believes solar geoengineering is inevitable, despite the relative lack of attention the technology has attracted to date. In a recently published book, the climate economist Gernot Wagner makes the case for this inevitability, yet he also presents a compelling argument for why much more research into geoengineering’s risks must be completed if it is to be put into practice. In today’s episode, he’ll explore why solar geoengineering is fundamentally different from other strategies that address climate change and why research programs into the technology must be tightly governed. We’ll also talk about why the path to solar geoengineering’s implementation, if it is indeed inevitable, is likely to stoke fierce policy debate and quite possibly geopolitical tensions.

Gernot Wagner is an economist at New York University and author of the recently published book Geoengineering: The Gamble. He is also a co-author of Climate Shock, which was chosen by the Financial Times as a best book in economics in 2015. Gernot, welcome to the podcast.

Gernot Wagner: Thanks, Andy. Great to be here.

Stone: The title of your new book is Geoengineering, but as you make clear to readers, the book is really about something more specific, which is solar geoengineering. The distinction is important, as you point out in the first few pages of the book. Why did you misname or maybe more accurately incompletely name the book?

Wagner: So you are right. Geoengineering itself is a misnomer for the more specific thing that most of the book is about. But to be clear, it’s important to talk about the full slew of technologies here, and it includes frankly two very different things. One is carbon removal, literally sucking CO2 out of thin air. That sounds expensive energetically and money-wise, and it is. That’s one set of technologies. Some call that “carbon geoengineering,” some also — I included, apparently from the sound of that title — subsume it under the term “geoengineering,” but it is really very, very different from this other set, solar geoengineering, which in many ways has the exact opposite properties, where carbon removal is expensive, relatively slow, and in some sense a real solution. It addresses the root cause — too much CO2 in the atmosphere. Solar geoengineering does neither of these things. So it’s fast. It’s cheap. And it is highly imperfect.

Stone: So just to point out, you have worked on solar geoengineering with David Keith, who is a Harvard physicist, who is I guess doing some of the leading research into the technology. Can you tell us a little bit about your background with that program?

Wagner: David and I co-founded the program, so I joined him. He was already there. I joined him from the Environmental Defense Fund, EDF, to start a research program. Harvard’s Solar Geoengineering Research Program, SGRP, for those in the know. It has been around now for about five years. It is the first of its kind, relatively sizable, but of course housed within one institution. It’s a research program that looks at this set of technologies in a holistic way. It’s not just the physicists. The chemists, the natural scientists, economists and of course many, many other social scientists are involved — still are involved; I am no longer involved in this research program — looking at this set of technologies from all different angles.

In many ways, of course, I would say this as a social scientist, but in many ways it’s not really the technology itself, the engineering, the natural science, as important as it is to do more research on that front. That, in many ways, addresses some of the most fundamental questions here because this is all about, or that conversation about it is all about the politics, the policy, the ethics, the philosophy of it. Should we be even talking about this technology?

Stone: Can you give us the quick 101 version of really what is solar geoengineering?

Wagner: It is an attempt, a large-scale attempt to alter the Earth’s albedo, its brightness, its reflectivity to essentially reflect more solar energy back into space. The principle is pretty much the same as why you and I wear white between Memorial and Labor Days, and why winter jackets are black. White reflects, cools what is underneath. Black attracts and warms what is underneath.

So painting roofs white is using this same idea. Now of course it’s using it in a very innocuous way, right? It affects the apartment immediately underneath the roof. It does not affect the global climate. Solar geoengineering, the most prominent solar geoengineering technology, is about altering the global albedo — albedo modification on a global scale — for example, through tiny reflective particles, aerosols, in the lower stratosphere.

Stone: So those would be injected into the stratosphere. I understand that sulfur dioxide is the material that would be used to do this. It’s light. It would reflect the light back into space.

Wagner: Sulfur dioxide is the best-studied one. Why? Because volcanoes have been doing this forever. So when Mount Pinatubo erupted in the Philippines in 1991, global average temperatures were about half a degree Centigrade, almost a degree Fahrenheit, cooler in 1992, ironically right around the time of the Rio Earth Summit. Temperatures were about half a degree cooler, which at that time was total global average warming due to us, humanity, emitting CO2 and was essentially masked by this volcanic eruption — though sulfates fall out of the stratosphere after 12 to 18 months or so. So by 1993, temperatures were back up, and of course, they have been increasing ever since.

Stone: Solar engineering really is, at this point, kind of a footnote in terms of attention amongst climate solutions. We don’t hear nearly as much about it as we might hear, say, about the carbon tax, which always seems to be in the news. So why did you choose to write this book on solar geoengineering right now? What’s the driver for it, if again, we’re not hearing a whole lot about it in the public dialogue?

Wagner: I would say two things. One, it is good that we don’t hear quite as much about solar geoengineering as about reducing CO2 emissions in the first place. That’s good. We have to cut CO2 emissions. There is just no way around it. And the last thing we would want to have happen is that talking about solar geoengineering detracts from the need to cut CO2 emissions. That phenomenon comes under the term “moral hazard.” It is real. It is a problem. And frankly the Newt Gingrich op-ed has already been written, that essentially said almost verbatim, “Ha! Found solution to climate change. Told you. Don’t need to cut CO2 emissions after all.”

He wrote that about ten years ago, at the height of the Obama era climate policy push for a national cap and trade system, emissions trading at the time. And of course that’s the wrong thing to deduce from talking about solar geoengineering. It is not, it cannot be a replacement for cutting CO2 emissions. In some sense, this is sort of the apology tour. It’s not the book tour. So sorry, no — don’t draw too much attention to solar geoengineering because frankly we have to cut CO2 emissions.

Now that said, yes, we should be talking, we should be researching. We should be researching solar geoengineering frankly quite a bit more than we currently do, not sort of leave it up to philanthropic money, private donors, fanciful university doing its own program. But yes, at the national, at the federal level — the National Science Foundation, the National Academies, and of course that is happening, that’s increasingly happening, but frankly there should be a lot more of that.

And I should add immediately around this “moral hazards” question of detracting from the need to cut CO2 emissions. Frankly we might also find the exact opposite. We do sometimes see the exact opposite, that talking about solar geoengineering in the right way, right? So not just grabbing it as, “Ha! Found solution!” But in the right way of, “Look, there is this set of technologies. It’s not a question of if, it’s when, and it’s not the first best thing to do here. It really isn’t.” We shouldn’t be starting with solar geoengineering.

So maybe talking about solar geoengineering in the right way actually pushes us to cut CO2 emissions more, the exact inverse of this moral hazard phenomenon, and frankly we see some of this. We see it with conversations about adaptation. Things are so bad already, we already have to adapt to what’s in store, which ought to push us to want to cut CO2 emissions even more so. And the same with solar geoengineering.

Stone: I want to dive a little bit more deeply why this is inevitable. You’ve talked about it being cheap. I think you mentioned the fact that the technology is relatively simple. It’s inevitable, but as you point out in the book, you’re not really necessarily so happy about that fact. It’s interesting that you spent so much time actually researching it. Tell us a little bit more about why you believe this is, if not inevitable, quite likely inevitable.

Wagner: Solar geoengineering has, in many ways, the exact inverse properties of mitigation of cutting CO2 emissions in the first place. What do I mean by that? We economists talk about this global climate problem often as a free rider problem. So it’s in nobody’s immediate self-interest to be cutting CO2 emissions, and if we do so, we aren’t really solving the global problem here, right? There are a billion of us. There are 200 countries and so on, so one of us going it alone isn’t going to solve it.

Now frankly we often make too much of this fact as economists, in the sense that it is increasingly no longer true that it’s not in U.S. self-interest, right? So when the international Energy Agency declares solar photovoltaic, solar PV, to be the cheapest form of electricity in history, you know, they’re onto something. Solar PV is cheap. Heat pumps are good. Induction stoves are better than gas stoves. Insulating your home is good, not just for the climate, but also for you living inside your home. It cuts down on your own energy bills. And so on and so forth, right?

There are lots of things we should be doing, could be doing, and that are increasingly in the money, that is sort of increasing the things that are “worth it” to do, almost regardless of how other people might react. And an electric vehicle is fundamentally a better product than one with an internal combustion engine, right?

So yes, you should be making that switch. That said, on a global level, there’s something to this free rider phenomenon. Solar geoengineering has, in many ways, the exact opposite properties — free driver, if you will. It is so cheap, relatively speaking. It is so fast, and of course it is also imperfect. But it’s the cheap and the fast that leads you to the opposite conclusion, that it’s not a question of motivating more people to cut emissions more. No, it’s the exact opposite, right? It’s stopping people from doing too much, too soon, stupidly.

And that’s what makes it interesting from an academic perspective, from a policy perspective. And yes, that leads to this conclusion of “not if, but when.”

Stone: So it sounds to me like the technology is fundamentally pretty much there, but what we would need would be the specially designed airplanes that could fly particularly high, be large enough to hold enough of whatever the materials that would be spread into the stratosphere. And I would imagine that’s at least a decade out. So on scale, the earliest this could happen, assuming everybody would get on board, which is a different question, which again we’ll talk about — we’re not seeing this for another decade at least at scale. Is that about right?

Wagner: Let’s put an S at the end of that word — decades, right? So okay, yes. If we were to — somebody somewhere — and I guess that matters, too, right? It’s the free driver property that also very much goes toward, “No, we don’t need a universal global agreement to get started.” Imagine the national security advisor to the prime minister, the president of a country particularly hard-hit by yet another hundred-year storm hitting the country within 12 months, 14 months or so. And yet another one of these extreme climatic events, tens of thousands of people, millions of people out of a job, lives, livelihoods lost. National catastrophe, and yes, that national government. Let’s say the Philippines, Indonesia, a country like that. Well, the national security advisor would be remiss not to mention the possibility. That doesn’t mean that anyone is launching anything tomorrow or next year, or even within a decade, but in all-out research effort and all-out mobilization effort, even by just that one country might well put us on a time scale that’s 10, 15, 20 years out. Is that the rational thing to do, the best thing to do from a global perspective? Maybe. Probably not. And that’s the problem.

Now we are back to this free driver phenomenon, but it’s not 8 billion free drivers around here, but yeah, there might be a few dozen countries that fall into this category.

Stone: In March of this year, the National Academies of Sciences released a report, and the title of that report is a bit of a mouthful, but I’ll say it right here. It’s “Reflecting Sunlight: Recommendations for Solar Geoengineering Research and Research Governance.” And there’s a brief passage from that report, a highlight that I just wanted to read here. And that is the following: It says, “The U.S. federal government should establish, in coordination with other countries, a transdisciplinary solar geoengineering research program. This program should be a minor part of the overall U.S. research program related to responding to climate change.”

Now the main theme of your book, or a main theme is that we need to understand the risks of solar geoengineering, and that seems to be what the National Academies are looking to understand more about. Can you tell us, what are the big questions that need to be answered? And I also just want to make a footnote. In that passage from the National Academies, it’s very much one foot in and one foot out. “Do it, but it’s going to be a small program.” So again, what are the questions that need to be answered?

Wagner: So quickly on this National Academies report. First of all, it’s not the first time the National Academies have talked about solar geoengineering. It sort of began in the ’90s, even. But frankly, very little has happened in the first couple of decades or so. And in some sense, appropriately so. And then in 2015, so six years ago by now, the National Academies came out with the first comprehensive report essentially saying, “Let’s take this more seriously than we are.” And then, yes, earlier this year was this report saying we should be researching this technology.

It doesn’t mean we should detract from other priorities, other climate priorities. And just to give you a sense of the order of magnitude, nationwide — I mean, it depends who is counting. But federal research spending on climate overall is somewhere, order of magnitude 3 billion dollars. So satellites are part of this. Not all of them, but weather satellites and so on are part of this. They cost quite a bit of money, but still, that sort of order of magnitude. The research program on solar geoengineering that the National Academies are talking about here, it’s order of magnitude 10 to 15 million dollars a year.

So a lot smaller. Now, that’s 10 or 15 million more than are currently being spent on solar geoengineering, and that’s important, but still, just to get a sense. And frankly, those 15 million in many ways shouldn’t come out of the 3 billion dollars. It should be in addition, right? Not that that really matters, because the orders of magnitude are so different.

Okay, what should that research be? Well, the operative word here from the National Academies report is this “transdisciplinary.” It is not just about the physics, the chemistry, atmospheric chemistry. That’s important, too. It really is. There is a lot more work that needs to be done to understand, for example, stratospheric chemistry and the interaction of any solar geoengineering intervention and stratospheric ozone. One of the most successful global efforts to address an environmental problem was the 1989 Montreal Protocol to attempt to do something about the ozone hole over the Antarctic.

We are, in fact, well on the way to stratospheric ozone recovery to plug this hole, to fix the ozone hole. It would be rather bad if solar geoengineering were to reopen that ozone hole. If there were some interactions here that we don’t yet know about, that pose particular risks. So it turns out we do know quite a bit already, and yes, it turns out, there are tradeoffs. They’re not quite as stark as any kind of solar geoengineering intervention would immediately reopen the ozone hole, but it would slow the recovery. That’s an important tradeoff.

There’s lots of additional research necessary on this question, and especially there’s research necessary on the question of: Okay, well, we know that if we send sulfur dioxide into the stratosphere, we have this negative tradeoff with stratospheric ozone. Sulfur dioxide happens to be an acid. What about using a base? What about trying the opposite? What about trying an intervention that might actually help stratospheric ozone. And there are hundreds of papers on stratospheric aerosols using sulfur dioxide. There are two or three — sort of a handful — of papers on calcium carbonate, limestone. That’s a base. And yes, in a climate model, that was the very first paper, it looks like it might be possible to attempt solar geoengineering using calcium carbonates, limestone, and actually have a positive effect on stratospheric ozone.

Now a subsequent lab experiment put a big asterisk to that very preliminary conclusion, but that’s not the point, right? That’s just an example of the kind of research that is necessary before anyone pulls any trigger anywhere on this question. And that’s the natural scientific side, and yes, then there are lots and lots of questions around social science, policy, policy formulation, moral hazard — this interaction of mere talk of solar geoengineering, solar geoengineering research, and that interaction with cutting CO2 emissions in the first place.

Stone: I don’t want to stay on this point for too long, but you made an interesting kind of footnote in your book where you said some research shows that actually if you — or suggests, excuse me — that if we were to move forward with solar geoengineering, people might actually take more action to mitigate, rather than less. So we have this fear of the moral hazard, and again to focus on what that is. That is if we use solar geoengineering to turn down the global temperature, hey — we can take it easy and not worry about mitigating. That’s the moral hazard. But you mention some research that shows just the opposite might happen.

Wagner: Yes, and actually the lead researcher here, Christine Merk, a German social scientist — Full disclosure: She’s a co-author by now, too. But this was very much her own paper five or so years ago. She put 600 Germans in a lab, or actually in online research in this case. So you create three groups of 200 each, and you present to one of these groups, “Okay, this is what climate change is. Are you now willing to offset your emissions? Would you use some of your own money to offset your emissions?”

The second group was told that climate change is really bad, so they were told more about climate change. And then the third group were told about solar geoengineering. And the moral hazard finding would be that those who were told about solar geoengineering would then say, “Oh, problem solved. Don’t need to offset my emissions. Don’t need to do anything to cut CO2 emissions,” right?

It turns out she found the opposite. Those who were told about solar geoengineering were more likely to offset more of their own emissions with their own money, their own euros in this case.

Stone: And is that because now climate change was real, because solar geoengineering was necessary, so they got scared?

Wagner: Kind of, right? As so often is the case, and this is actually my follow-on work with her now, trying to figure out what’s actually going on, right from people’s minds. But yes, one hypothesis is when serious people talk about, “What? Solar geoengineering, this sounds pretty scary! Maybe there is something to this claim of a problem after all.” Sort of the frying pan effect. You get whacked over the head with this. “Oh my God, wake up call. Let’s finally cut emissions!”

And frankly we see that in other — we see that with adaptation. So there’s a historic analog here. In the 1990s, environmental groups — Al Gore is vice president and was on the record saying, “Let’s not talk about adaptation because it detracts from the need to cut emissions in the first place. Let’s solve this thing first. Let’s get Kyoto done,” right? In 1997. That sort of thinking.

Now fast-forward ten years or so, early 2000s, and of course environmental groups started talking about adaptation, because frankly we all realized that talking about adaptation actually draws more attention to the need to cut CO2 emissions. Because when you talk about, “Oh my God, this is so bad. We need to invest in resiliency efforts and adapting to the sea level rise that’s already happening and fortifying our infrastructure and so on.” And all of that comes with massive costs, which it does.

Well, that shows how important it is to address the underlying problem. Okay, well, fast-forward twenty or so years, and now we are in this, in a very similar situation with solar geoengineering. Now, I’m not saying that solar geoengineering should go the way of adaptation, right? It becomes sort of the commonly accepted thing ten years from now. Not at all. But this inverse moral hazard, mere conversation. You and I are now talking about solar geoengineering leading us to cut CO2 emissions more, wanting to cut CO2 emissions more. This inverse moral hazard is apparently very much real, and of course the whole point — the best way to address moral hazard is to invoke its inverse. It’s not to try to minimize moral hazard, but to turn it the other way, to basically say, “Okay, you think this lets you off the hook for cutting CO2 emissions? Guess what? No, it means we need to cut it even more.”

Stone: You know, I want to jump forward with this issue of governance that the National Academies pointed out and also tie into what you just mentioned about solar geoengineering becoming at some point the commonly accepted thing. Now governance is key, the National Academies points out, and one reason is that governance optimally will help avoid the inevitability, if that is warranted, by avoiding a slippery slope whereby research and lots of investments into this technology leads to solar engineering being implemented pretty much through inertia and momentum.

The National Academies report says that research needs what they call an “off-ramp” to make sure that we aren’t destined to go down that path of inevitability, again, if it’s warranted. Can you tell us a little bit more about the importance of the slippery slope, the off-ramp, and what that really means?

Wagner: Here is the first thought that comes to mind when anyone talks about solar geoengineering, right? Why do I study it? Why do many scientists, natural and social, study this phenomenon in the first place? For many of us, it was, in fact, this realization: Look, climate change is so bad. It is. It’s much worse than anyone had previously thought, in a broad sense. The more we know, the worse it seems — unmitigated climate change. And meanwhile, our pace of action just isn’t keeping pace here. So we are just not solving the problem.

Solar geoengineering does seem, meanwhile, to do a lot of good, potential good, right? The net benefits are potentially large. That’s sort of the starting point, which is another way of saying, “No, this research, including the off-ramp of moving away from inevitability, is not just about, ‘Let’s make sure to squash this technology in its infancy.'”  There is a lot about, “Yes, let’s make sure we do research the risks. Let’s make sure we know what we are getting ourselves into,” absolutely. But frankly, for many of us, and I included, this is not just about, “Let’s figure out all the risks here to then make sure we intelligently talk about why never to do this ever again.”

Yes, there are risks. There are uncertainties. But the starting point is that yes, there are also potentially large, sizable orders of magnitude net benefits. So it’s not just about the risks. That said, the ultimate criteria in many ways isn’t this benefit/cost analysis, isn’t looking at the net benefits. It’s about risks versus risks. It’s about risks of unmitigated climate change, and they are large. They are there. They are potentially much larger than most of us think.

And the risks of solar geoengineering. And they are, too. They are clearly there. There are clearly risks. So it’s about errors of omission versus errors of commission, to use a fanciful, philosophical description here. It’s basically about looking at the risks on both sides.

Okay, now, if and when we do that, and yes, we should be studying this topic much more than we currently are, we need to be able to have this sort of off-ramp the National Academies described there in their report that talks about not just researching this because we’re inevitably slipping, sliding towards it anyway. “There’s nothing much to do, so might as well research it, to not go into this uninformed.” Yes, there is something to that description, this free driver effect, but some of this research very much ought to focus on what to do to avoid sliding towards this inevitability.

Stone: I want to jump in on that, because there’s a really poignant point you make in the book, just on this issue about the off-ramp and the slippery slope. In the book, you say that research — and this is getting into the policy of this — you say that research should really not be done under the auspices of the government or performed by the government. You actually say the research should be done in universities, and you’re explicit about that. And if it’s ever implemented, then the implementation should be as the result of elected officials making that decision.

So it sounds like you’re thinking that there’s a danger of the slippery slope if the government or something like that would get involved with that. Tell us a little bit more about that.

Wagner: Okay, so define “government,” right? So ideally, this is a global —

Stone: Not the CIA doing it.

Wagner: So exactly, right? There’s certainly a lot to that, so let’s not have this be a military operation. Let’s start with that. That’s pretty clear. At the same time, there is sort of this ideal. Global democracy, we all get together and vote. This is sort of this fanciful, hyper-rational world, right? Jacinda Ardern who is doing a good job in New Zealand actually gets promoted to World President. Right, that’s how the world works? And then we do the most rational thing possible on a global level.

Okay, look, that’s not how the world works. We don’t do the most rational thing. We wouldn’t be talking about climate change if we had done this all along. So we’re in a world where this best rational approach is just not an option very often, right? We don’t do the first best. We don’t do what the science tells us, for the most part, sadly.

So now we need to roll with the punches. What does that mean? What does it mean to design a research program in light of that real world that we live in? One is, on the one hand, yes, you want to create these walls. You want to make sure that it is not the military calling the shots. It’s not — especially military in an undemocratic country calling the shots. And then sort of confronting the world and saying, “Oh, look guys, we are doing this.” Right? There’s not much you can do. Covert operation style.

At the same time, you certainly also don’t want the scientists. It doesn’t matter where they work, whether they’re an employee of the government or at private institutions, at universities, public or private. It doesn’t really matter. You certainly don’t want the science, the scientists to be calling the shots. The decision of whether or not to deploy, and in which form to deploy, is very much a public decision. It ought to be a decision that “the public,” writ large, makes. What does that mean practically in a representative democracy? Elected leaders.

If there were to be a proper policy process led by the current White House that comes up with, “Oh, yes, we should be researching this topic to the tune of 10 to 15 million dollars a year, let’s say. And the U.S. Global Change Research Program, USGCRP, the government agency coordinating these 3 billion or so dollars worth of federal climate research, right? If that program, then, also were to add a 10, 15 million dollars a year solar geoengineering research program, yes, that’s a very different world, right? In that case, it is the elected representatives, the government deciding on our behalf in a more or less democratic fashion, democratically-elected representatives in a semi-rational policy-making process to come up with this conclusion and say, “Yes, let’s do this research,” on the one hand. And then of course, much more so than the research question, any sort of deployment decision, right? Dozens of years down the line, of course must be because of public conversation, because of a democratic process — not because some scientists somewhere decided to go that way.

Stone: This gets really interesting, and here I think we’re going to dive deep potentially into some of the geopolitical considerations here. But you’ve just been talking right now about this in the context of national level decisions, but it’s really important to reiterate here the fact that this is a global solution or a global technology —

Wagner: Intervention, yes.

Stone: Intervention — that’s the right word. Thank you. You inject this substance into the stratosphere, and it doesn’t just stay above the United States or whatever country does it. It scatters around, just like volcanic dust does. So to do this right, and this is where things get really, really complicated, and I wonder if there ever can actually be consensus on this globally, but you would need, I would think, a global consensus on whether geoengineering should be implemented, because it affects everybody. And unlike implementing a carbon tax or whatever it may be, this really is an active process, an active impact it has on the climate, or would have.

It’s hard for me to imagine a situation where you get buy-in from every single country, and they say, “Hey, go ahead and do this because the impact” — as I understand from reading your book, it’s pretty uniform around the world. I mean, geoengineering would affect temperatures pretty much equally everywhere,  but whether one country thinks that’s a good thing for its own interests or not, I mean it’s a can of worms like this, you know?

Wagner: It is. So how much more time do we have?

Stone: As much time as you want to give us and the listeners can bear.

Wagner: Okay, so 18 hours in, we’ll still be talking. So yes, this is now where it gets academically very interesting. Let’s start with that. And of course, yes, there are very, very hard questions here. But let me just pick up on one thing you said. You mentioned something like, “Now we need global consensus.” Okay, ideally, sure. No, I shouldn’t say dismissively, “Sure.” I mean yes, right? This is a potential global intervention, so it’s only fair to allow everyone a seat at the table, a voice. But again, sadly, that’s not how the world actually works. So we don’t have to go back too far in history. Cold War-type interactions, let’s say. Sure, one country elected its leaders and sort of presumably had sort of a democratic process leading up to some of these decisions, of course — the U.S. now. Well, the rest of the world, nobody asked. I grew up in Austria. Nobody asked me or my parents or anyone in Austria how we felt about the fact that there are two superpowers arming themselves in this Cold War.

So in reality, no, we don’t have global democratic processes leading up to decisions around stuff that does affect the entire globe. So here, too, while ideally, of course, let’s get all 8 billion of us in a room, and we’ll sort this one out, and we’ll vote. Well, we don’t. That’s not how we decide. And we also don’t decide often globally sort of in terms of, “Let’s all get together — all heads of state get together and dole this one out.” I mean, yes, the United Nations, the U.N. Climate Talks and so on. But the big feature, the most important feature here around solar geoengineering, and now we are back to this free driver property, is unlike with cutting emissions, where it is about motivating individual countries to do more. It’s about getting all of us to agree to do more.

Solar geoengineering for better or worse, and perhaps mostly for worse, has the sorts of features where it doesn’t depend on everybody agreeing. We don’t need to wait around for everyone to get on board for us then to be able to move forward.

Now first of all, who is the “us,” who is the “we” in this case? Well, if it’s possible, since it might be possible for dozens of individual countries to go it alone without global buy-in, without the help from others. Now we’re in this world of this free driver phenomenon, where again, the name of the game is not to motivate people to do more of this, but maybe to stop individual countries, to stop them from doing too much, too soon, stupidly — at least guiding them.

So now the conversation is very different. The conversation is not about, “Let’s all agree to take a careful step forward here,” but maybe the conversation is along the lines of, “Oh, they over there seem to be doing something here on solar geoengineering. Let’s study what’s happening. Let’s figure out what the heck is going on.” And at the same time, via diplomacy, via U.N. fora and so on and so forth, bilateral diplomacy. Make sure we nudge, we guide, coax this conversation in the right direction.

In many ways, quite the opposite of what’s happening at, let’s say, the U.N. Climate Talks where, yes, free rider phenomenon. The name of the game is to motivate more to do more on the emissions-cutting front.

Stone: You make another hypothetical in your book that I just wanted to talk about here. It’s an example where the European Union doesn’t get behind solar geoengineering at some point in the future because Germany’s Green Party — and this is completely hypothetical.

Wagner: It is, yes.

Stone: Okay, in a hypothetical coalition government in Germany, the Green Party nixes the idea, okay? So the question I have here is: What is the political alignment of geoengineering? Could we see significant support from the left and the right, and opposition from both sides? Does it go along the lines of what we think about here in the United States about the traditional conservative/liberal divide on dealing with climate change?

Wagner: The short answer is yes and yes. Could one conceive of a correlation where those who think that climate change is really bad and we need to act would also be motivated to want to do the most on the solar geoengineering front? So in some sense, yes. Actually, most of us scientists working on solar geoengineering research came to this topic basically by first spending quite a lot of time studying climate change in the first place.

Politics, you could imagine a certain subgroup of the German Greens who want to do something about climate change, right? They hate climate change, but they hate solar geoengineering even more. And then maybe there is another set of environmentalists, typically left of center politically, who very much hate climate change, hate unmitigated climate change, want to do something about it, and consider solar geoengineering something that at least ought to be researched, ought to be looked at.

So now you have conversations among progressives, among those on the political left, and there is no immediately clear answer. There’s certainly no clear answer of who is right. There’s no, “Oh my God, you are right.” You know, “I am right, and you are wrong,” right? Even though everyone would say that, there’s no objectively right answer here, a priori. So yes, suddenly you have yet another split potentially within the environmental movement. Some who would want to do more on the solar geoengineering front, and frankly many others potentially who would not.

Meanwhile, in many ways the U.S. here is sort of somewhat easier here. Left, right — you only have two parties, two large parties. And there actually it seems unclear at the moment how solar geoengineering would align here, because you could imagine if you are interested in maintaining the status quo, keep burning fossil fuels. Then you would say, “Okay, fine, and solar geoengineering is the way out.” This is kind of like Newt Gingrich and his op-ed over ten years ago saying, “Found solution to climate change. Don’t need to cut CO2 emissions.”

Okay, but in saying so, you need to acknowledge that climate is a real problem in the first place, and that we do have to address it. You may not want to address it by cutting CO2 emissions, which, by the way won’t be a mistake, but you first need to accept that climate change is, in fact, real.

So now you have this potential for solar geoengineering to really throw open the climate conversation because suddenly you jump-start this conversation of, “Okay, if we want to have a serious conversation about solar geoengineering, we first all need to agree that climate change is a real problem, and frankly it’s so bad that we do need to, in fact, consider solar geoengineering, as well.”

So yes, talk of solar geoengineering does have the potential to create some interesting new alliances on the climate policy front, writ large.

Stone: I’d like to ask: When will we know if we have sufficiently enough answered the questions around the potential risks and benefits of solar geoengineering that we could actually arrive at that do-it/don’t-do-it decision? What do we really need to know? When will we know enough?

Wagner: This is not going to sound like the biggest cop-out answer here, but we won’t know. There is no — Okay, so here is the 20-point list of things that we need to answer, and once we have checked 18 out of those 20, we are good to go. There is no such thing. It’s a very fuzzy line, if there is even a line. In many ways, there is never going to be enough information. There is always more work one could do, right?

And sometimes the more research we do, the more open questions we’ll have, right? It’s the typical phenomenon which then can take on a life of its own. So no, there is no single bright line here, which of course makes this such a difficult topic, right? Like how will we know what we don’t know? How will we know that we know enough? Well, we will never be in this clear-cut category of saying, “Okay, check the box. The science is done. Let’s hand this over to the politicians.” That’s one of the major difficulties.

Now just to be clear, solar geoengineering here is not unique. It might exacerbate some of these issues. It might crystallize some of these questions. It might make it very clear that this “not knowing” is in many ways costly, extremely costly. We ought to be doing more research, yes. But when will we know that we have done enough?

Well, in short, we won’t, and that’s what makes this such an interesting topic to explore, both as a scientist, as a social scientist, and of course also then, vis-a-vis climate energy policy.

Stone: Gernot, thanks very much for talking.

Wagner: Thanks so much.

Stone: Today’s guest has been Gernot Wagner, a climate economist at New York University and author of the recently published book, Geoengineering: The Gamble.

Thanks for listening to this episode of Energy Policy Now. To make sure you get future episodes delivered to you, subscribe on Apple Podcast, Spotify, or wherever you get your podcasts. And to keep up to date on all the latest research and events from the Kleinman Center for Energy Policy, visit our website. Our address is kleinmanenergy.upenn.edu. Thanks for listening to Energy Policy Now, and have a great day. 


Gernot Wagner

Clinical Associate Professor, NYU
Gernot Wagner is a climate economist. He teaches climate economics and policy at NYU, where he is a clinical associate professor. Wagner is a 2021-2022 Kleinman Center Visiting Scholar.

Andy Stone

Energy Policy Now Host and Producer
Andy Stone is producer and host of Energy Policy Now, the Kleinman Center’s podcast series. He previously worked in business planning with PJM Interconnection and was a senior energy reporter at Forbes Magazine.