A Science-Fiction Solution to Climate Change?

Published May 11, 2021

Dr. Peter Frumhoff weighs in on a controversial idea for slowing down global warming: shooting particles into the atmosphere to cool the planet.

In this episode

Colleen and Peter talk about

  • How realistic geoengineering is as a tool to fight climate change
  • Its long term sustainability
  • Some of its potential risks
Timing and cues

Opener (0:00-0:34)
Intro (0:34-1:57)
Interview part 1 (1:57-13:34)
Break (13:34-14:30)
Interview part 2 (14:30-22:09)
Throw (22:09-23:10)
End segment (23:10-27:58)
Outro (27:58-29:00)

Related content

Editing: Omari Spears Music: Brian Middleton
Additional editing: Brian Middleton and Colleen MacDonald
Research and writing: Pamela Worth
Executive producer: Rich Hayes
Host: Colleen MacDonald

Full transcript

Colleen: Peter, welcome back to the podcast.

Peter: Thanks, Colleen. It's great to be here.

Colleen: So, I wanted to talk today about the recent National Academies report that you are involved in. But first, can you start by giving just the briefest definition of solar geoengineering?

Peter: Sure. So, solar geoengineering broadly refers to proposed approaches not yet realized to cool the earth by reflecting sunlight, solar radiation back to space. There are two main approaches that are being researched. One is called stratospheric aerosol injection, which essentially mimics a large volcanic eruption. The notion would be to send aerosol particles to the stratosphere, which would reflect sunlight globally, and the other is called marine cloud brightening, which would entail spraying sea salt into low lying and marine clouds to enhance their size and their reflectivity.

Colleen: So, let me ask you a couple of just quick clarifying questions. So, is this a permanent solution to global warming or is it only as long as we're doing this practice?

Peter: Well, let's be really clear. It's not a solution to global warming at all. It's at best a kind of stopgap measure. The only permanent solution to global warming is to reduce emissions, that is to say, to stop sending heat-trapping pollution, carbon dioxide, and other heat-trapping gases to the atmosphere. And we actually need to do that. And we can do that quickly and decarbonize our economy. The notion of solar geoengineering is as a potential additional climate response to limit warming, if in fact we cannot limit warming sufficiently quickly come by the primary method we need to address, which is mitigation.

Colleen: To give people an idea of the potential harms, what are some worst-case scenarios that might happen if we employed this technology?

Peter: Well, there's simply a lot we don't know. So, for example, in the case of stratospheric aerosol injection, we know from volcanic eruptions and the response of the Earth's climate to the extent of aerosol particles that are sent to the stratosphere. They would fall out over time. But we have computer models to help us begin to understand what some of the other effects [00:03:30] would be with respect to changes in precipitation patterns, for example. But there's a lot that remains to be understood about the impacts on Earth's ecosystems, on the ozone layer, and in other patterns of climate changes. So it's really important that before any decision to deploy solar geoengineering might ever get made, that we better understand not only what the impacts might be, but how the technology could be responsibly or might be responsibly governed. There's a big landscape of unknowns here. There are significant risks to changes that we can't now foresee. And so, it's very important that any deployment decisions should ever be made, is based on much deeper understanding of both the risks and potential than we have today.

Colleen: That takes me back to the report from the National Academies of Science Engineering and Medicine that you worked on. And it largely focused on governance and the potential for beginning experimentation on solar geoengineering. So can you tell me about the report and what some of the conclusions were?

Peter: So, the charge to the committee of the National Academies in writing this report was to develop a research agenda for understanding solar geoengineering technologies as a potential climate response, to understand the potential impacts, both positive and negative, on ecosystems, and the atmosphere, and on human society, and understand the technical and social feasibility of these technologies. And then simultaneously, to recommend a set of mechanisms by which research into solar geoengineering might be responsibly governed. And that's what we did. The academy panel that I served on recommended that the U.S. government start a bounded solar geoengineering research program over the next five years that would look at a range of technical issues, from physical science impacts, atmospheric chemistry, to questions about ethics, public participation and decision-making about solar geoengineering research, and a whole range of social science questions about how a program might be designed, how we might build capacity in developing countries to participate meaningfully in such research. And it also simultaneously recommended a set of guidelines for how research should be governed. For example, to provide tight limits on the extent of outdoor experiments that might be done so as not to have experiments that would be at such a scale as to have an impact on the Earth's climate, to make sure that there is a permitting system for such experiments, to make sure that there is meaningful public participation in decision-making about how research is done and to ensure that there's transparency and international cooperation in the research that's developed. And to put this in the responsibility of the federal government to coordinate this research under the auspices primarily of the U.S. Global Change Research Program, which is the same cross-agency body within the federal government that currently is responsible for the National Climate Assessment.

Colleen: Did the report touch on how to have meaningful and inclusive public engagement in the decision-making process? This seems very important, and particularly given the recent scrapping of the Harvard SCoPEx experiment in Northern Sweden. Can you talk a little bit about what happened there?

Peter: Yeah. So let's start by talking about what SCoPEx is. SCoPEx is a experiment being proposed by a set of researchers at Harvard University in which they want to release a very small amount, about 2 kilograms, of aerosol particles into the stratosphere in order to test some very basic mechanisms about their dispersal properties. The aerosols that they're planning to release are calcium carbonate, essentially, chalk dust. And they want a better understand how these particles might be dispersed and how they might then incorporate that understanding into better computer models to understand the mechanisms by which that might be one day deployed in stratospheric aerosol injection. So they've raised funding mostly from private sources, including, notably from some fairly wealthy billionaires like Bill Gates, to initiate the research. It's just bringing a gondola tethered to a balloon into the stratosphere. They're proposing to do just some initial test flights of the mechanism of the balloon in an area in Northern Sweden that was scheduled originally for summer of 2021. And they got significant pushback on the proposal to do this mechanical test of their experiment by a number of Swedish environmental groups, and notably, by the council of the Sami people, the Sami people, or the indigenous people whose native lands are in this portion of Sweden and other areas of Northern Europe. And Sami Council said, "No, thank you. We don't want this research here," not because they necessarily saw the experiments themselves or the test of the equipment itself as dangerous or risky, but rather because they saw the experiment as intentional towards potential future deployment, something that they feel strongly that they did not support.

And the Harvard researchers, together with an advisory committee that had been established to provide recommendations, among other things about public engagement, had not unfortunately taken the time in advance of announcing the test flights to consult with the Sami people or other communities in Sweden over whether they would see these flights as legitimate or not, as appropriate or not. And, , in hindsight, that was a significant error pointing to the importance of meaningful public engagement in decisions about solar geoengineering because the Sami community, as represented by the Sami Council said, "No, we don't want this." And so that's led to the postponing of the test flights. And as I understand it, the researchers at Harvard are now considering whether to look elsewhere to do these tests, to do this experiment. And if they do, I think they will need to rectify this oversight and make sure they do follow some meaningful solicitation of input from the public's, both in the region in which the experiment is being proposed and more broadly, to get a bead on whether they can and should go forward.

Colleen: Peter, what would you say to people who see this as the first step to endorsing geoengineering as a climate solution?

Peter: Well, the important thing to recognize is that solar geoengineering is absolutely not a climate solution. It's at best stopgap measure, should we get into a moment in which we're seeing seriously disruptive climate change and one or more nations decides to move forward with it. Right now we have a research enterprise in solar geoengineering that's ad hoc. It's fragmented. It's mostly funded by private sources, venture capital, individual donors, and so on. It's not subject to any meaningful governance and oversight. And so, the recommendations of the academy panel were to try to provide a more robust oversight mechanism by bringing this into a federally funded program with real rules and guidelines for how that research should be done. It's absolutely essential that any research in this space be contingent upon a recognition that mitigation, reducing emissions, and adaptation to unavoidable impacts are our top-line solutions to climate change. The Academy panel was adamant about recognizing that at best solar geoengineering is only an additional possible climate response. But the fact is, we're not in a position today to make informed decisions about whether or not it might ever be a potential climate response. And so, the guidance from the Academy is to ensure that the research is designed in such a way that it's just as likely to lead us to a decision that concludes that we should never seek to deploy those as to one in which we might understand some bounded conditions under which it might be appropriate. But in no way should furthering of research in solar geoengineering responsibly governed be seen as a substitute for mitigation. And if it ever became one, that research should be stopped immediately.


Colleen: What mechanisms are in place to stop the research if necessary?

Peter: Well, the guidance of the Academy was to create a research program with oversight, and if you will, off-ramps so that there are mechanisms in place in the governance of it to stop research that's either not productive or tells us that the work is too risky and should not be continued. The mechanisms are transparency. The mechanisms are robust oversight. The mechanisms are meaningful public participation in decision-making, as there is for any body of research that's potentially risky. And so it's very important that this be designed with those guidelines in mind. My greatest concern, to be honest, Colleen, in the context of supporting a federally funded research program, is to make sure that the governance mechanisms are taken up just as fully as the research proposals are. That is to say, we wanna make sure that the recommendations on governance and the recommendations on research are seen as an integrated whole. It's not a kind of choose one but not the other set of options. And so, it'll be very important to watch how the U.S. government and indeed the other governments might decide to move forward building on these recommendations, and work to ensure that the governance mechanisms are taken up just as fulsomely as those that are suggesting that research should be pursued.

Colleen: Right now, well, let's use SCoPEx as an example. If they want to launch their experiment, can they do that? Do they need permission from anyone, or can you launch something into the atmosphere?

Peter: So in the case of SCoPEx, their advisory committee did a review in consultation with Swedish legal experts and came to the conclusion that their ability to launch the experiment in Sweden was consistent with Swedish law. And of course, the decision about whether a particular experiment would be appropriate or not is gonna be contingent on the laws of whatever geography and jurisdiction the experiments proposed to take place in. The laws in the United States are quite limited with respect to solar geoengineering. And they certainly need to be strengthened, which is one reason, for example, that the Academy panel recommended a formal permitting system to facilitate overview of proposed outdoor experiments in the United States. So, it's legally viable, according to that review in Sweden, but legally viable isn't the same as socially acceptable. And what the SCoPEx experiment researchers found was that at least with respect to the Sami people, as represented by their Council and a number of environmental groups based in Sweden, it was not. And so, more broadly, as we build out a research program on solar geoengineering to explore its risks and potential, really a core question is to better understand, not just in Sweden, not just the United States, but globally, what's the social acceptability, the social feasibility of both research and potential deployment of solar geoengineering technologies? We don't really know the answer to that yet.

Colleen: So, Peter, how have your colleagues who've been working on climate change for years reacted to this report?

Peter: Well, it's an important question, Colleen. You know, all of us who've been working hard to tackle climate change would really rather not be talking about risky technologies when we know what the core solutions are, right? We know what we need to do. We need to bring our emissions to zero, to net-zero, and not have any more carbon going into the atmosphere than coming out of it. We need to adapt and prepare to be resilient to the changes in climate that are now unavoidable. We know what we need to do. The technologies are available. It's really a matter of political will. It's a matter of time. But we've waited for so long to begin to address the climate problem and its root causes that we're in a tough place. I think, by and large, other climate scientists that I speak with, both at the Union of Concerned Scientists and, more broadly, see value in research in solar geoengineering, recognize that it needs to be bounded and strongly governed, and believe that we would be far better off if we put as much time and attention as possible into decarbonizing our economy and limiting the prospect that, whether it's the U.S. or another nation, might decide to take it into their own hands to limit warming at some point using solar geoengineering technologies. But we definitely need some more information so that if anyone decides to use these technologies, we're better prepared to make informed choices about whether or not that should be furthered or stopped. Colleen: And just to be super clear, no one should be getting the idea that you or the Union of Concerned Scientists endorse solar engineering, right? Peter: Well, unequivocally we strongly oppose any deployment of solar geoengineering technologies. We recognize that they currently pose significant environmental, ethical, and geopolitical risks, and are not at all appropriate to be deployed. At the same time, we believe that researchers should better understand the potential and risks of these technologies primarily using computer modeling techniques and monitoring the climatic impacts of events such as volcanic eruptions, basically, the kind of natural analogs that we see to potential solar geoengineering technologies. And we strongly oppose any stratospheric tests of these technologies at a scale that could have any measurable impact on the Earth's climate. If any small scale experiments move forward, we lay out several criteria by which we believe they must be and they must adhere that they be governed by independent mechanisms to ensure that the experiments are of high quality, and value, and pose no environmental or legal or social risks, that funding for solar geoengineering experiments come only from governments and other entities that support mitigation and adaptation as their first-line solutions to climate change. And that importantly, really can't stress this enough, that any governance mechanisms for solar geoengineering must be transparent. They must be inclusive, and they must ensure meaningful engagement with climate-vulnerable communities and the public in order to ensure that public participation in decision-making over such research is full and transparent.

Colleen: Well, so, Peter, this all sounds like a bad science fiction movie. Do you have any good, old-fashioned good news that can bring to our listeners?

Peter: Well, you know, people worry a lot about what's called the moral hazard of talking about solar geoengineering that even discussions of it might lead us to reduce our commitment to addressing the core problem by reducing our emissions. We all know what we need to do. And that worry has led folks to be quite concerned about possible research in this space actually exacerbating the problem. The fact is, is that there's just as much uncertainty about how people will respond to talking about solar geoengineering as there is about what its impacts might be. And there's some evidence to suggest that by having conversations about this technology and the recognition that we're at a point at which people are beginning to seriously consider it, that that might actually lead us to accelerate our ambition to reduce emissions in order to avoid any prospect of having to consider deploying sunlight reflecting technologies. The jury is definitely out on this. I know for me personally, that the time that I've spent wrestling through the question of research and governance of solar geoengineering has led me to recognize that there's nothing more important that we can and must do than to aggressively and ambitiously bring our emissions to zero as swiftly as possible, and try to leave our ourselves, and our children, and our grandchildren, a planet in which we're not disrupting it with either fossil fuel technologies or solar geoengineering technologies. So it's not exactly a hopeful note but it's a prospect that these conversation is necessary, if undesirable, will actually motivate us even more to accelerate our ambition to solve the climate problem, as we know we must by reducing our emissions.

Colleen: It's a real wake-up call.

Peter: Absolutely.

Colleen: Well, Peter, thanks for joining me on the podcast. This has been, you know, not the most upbeat conversation but an important one. And I thank you for taking the time.

Peter: Thanks, Colleen.

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