Should Global South scientists engage in solar radiation modification research?

Below are edited highlights from the full C2GTalk interview shown in the video above. Some answers have been edited for brevity and clarity.

Welcome to C2GTalk, a series of one-on-one interviews with influential practitioners and thought leaders to explore the governance challenges raised by emerging approaches to alter the climate.  I am Mark Turner, Senior Communications Consultant with the Carnegie Climate Governance Initiative (C2G), and I am speaking today with Inés Camilloni, a professor in Atmospheric Sciences at the University of Buenos Aires, who was recently appointed as vice chair of the Intergovernmental Panel on Climate Change’s (IPCC) Working Group I, which explores the physical science basis of climate change. 

Over recent years Professor Camilloni has become an increasingly prominent public speaker on climate issues, including on the science and governance of solar radiation modification (SRM), also known as solar geoengineering.  Her team in Argentina is researching the regional and local effects that SRM could have on the hydro climate of the La Plata Basin, which is both one of the largest drainage basins in the world and home to more than 160 million people. 

Professor Camilloni was also co-author of this year’s independent expert review under the UN Environment Programme (UNEP) on solar radiation modification research and contributed to a United Nations Educational, Scientific, and Cultural Organization (UNESCO) report on the ethics of climate geoengineering.  In late 2022 she called for more research into the challenges around SRM in a talk at TEDxRiodelaPlata called “Solar Engineering: Who Controls the Earth’s Thermostat?” 

Inés Camilloni, welcome to C2GTalk. 

Thank you very much. 

Let’s start with congratulations on your recent appointment as vice chair of the IPCC.  Can you tell us a little bit about what your work there will entail? 

To be vice chair of the IPCC (Intergovernmnetal Panel on Climate Change) is to work together with the co-chairs of the IPCC and also some members of the board of the IPCC.  We had to prepare the work plan for the Seventh Assessment cycle that is just beginning.  Also we have to work closely with the authors to advise and train them in some issues related to how we manage uncertainties, for example, in the IPCC, to be also in the conversations of the reports, and also to be part of the selection of authors and researchers to be part of these meetings in preparation of the reports.  So it is a very active role for the next seven years. 

That is fascinating.  Before going on to the other questions I have planned, I am interested in this area of uncertainty and how you communicate it.  I am not sure how much you can say now, but I would be very interested in your top line of how people deal with uncertainty in climate science and how you explain it?  

We produce climate scenarios for impact studies or just to show the way we can expect climate to be during the next decades.  We have scientific uncertainties related to these projections and also because we have many global climate models to produce this information.  There are some methods we can use to compute these uncertainties.  Also we have uncertainties related to the different scenarios.  We do not really know how much CO2 (Carbon) we will continue releasing into the atmosphere, and there are different strategies to estimate these uncertainties and communicate them. 

What do you see as the big challenges to be addressed by the IPCC in this Seventh Assessment cycle?  What are the big themes we are looking at? We know a lot already about what is happening with the climate.  What more do we need to know? 

I think one of the big things we should do is produce more concise reports.  The Sixth Assessment report of Working Group I weighed more than 6 kg in the printed version, two volumes.  It is a very hard task to read all of this information.  It is good maybe for the scientific community, but we should produce something more concise and more readable than what we have now. 

The other issue is that up to now the idea is that the IPCC should be policy-relevant but not policy-restrictive, but there is an increasing need for proposing solutions.  There is some overlap of this idea of saying what we can do and what we should do and not being restrictive.  I think this is something we should discuss more because everybody wants the IPCC with a stronger voice not only in scientific issues but also in the messages about the urgency about what must be done during the next years. 

I know there is a lot of debate around this, so I look forward to seeing how that evolves. 

Let’s turn to your work on solar radiation modification, which is obviously something that C2G is interested in.  First of all, just on a simple level, what is it, and what attracted you to work on this idea? 

Maybe I will start by answering the second question.  I was lead author of the IPCC 1.5°C report on the impacts and risk assessment chapter.  One of the results that came from that report was that to reach the 1.5°C temperature target we should reduce in a very dramatic way carbon dioxide emissions into the atmosphere, and the number was frightening because we should reduce more than 40 percent compared to emissions in 2010.  In this chapter about impacts and risks we showed that with the half-degree between 1.5°C and 2.0°C we run an increasing risk associated to this half a degree, so the urgency to reduce the emissions into the atmosphere is something very important. 

When I saw these numbers and what we are doing now, that emissions are still increasing, I started listening to this idea about solar geoengineering, climate engineering, or climate intervention, that there was something else in this menu of strategies that we could consider when we talk in the solution space about climate change. 

In particular in the Global South or in Latin America nobody was talking about this.  I decided that we should have local information and should know more about the potential impacts.  With those numbers in mind it seems sometimes that we are going in that direction if we want to avoid the worst risks of climate change. 

We will definitely talk in a little bit about the Global South and its involvement in this research. 

Stepping back, first of all we will address one of the big issues raised by SRM, and also how do we talk about it and analyze it?  It is a potential method to reduce climate risk, but it creates potentially new risks of its own.  How can scientists analyze and communicate these two different risks and balance them out, especially given uncertainty, which we touched on earlier, things we know we don’t know and things we don’t know we don’t know? 

The first thing is to think about what we do not know yet and to identify the risks for different regions and different sectors.  Also we need to keep in mind that there are different strategies of solar radiation modification, including introducing aerosols into the stratosphere, marine cloud brightening, cirrus cloud thinning, or changing the albedo of the Earth’s surface.  There are different strategies, and the potential consequences of each of these strategies are different. 

The first thing is to identify which strategy for what — do we want to cool the whole planet, do we want to cool some area, or protect some region from increasing temperatures, and for this we can use, for example, marine cloud brightening.  If we want to cool the whole planet, maybe we should think of stratospheric aerosol injection. 

It is not a single question because it depends on the strategy.  Even when we consider stratospheric aerosol injection, for example, if we want to cool the planet by 1.0°C or by 0.5°C or for how long, so the potential risks are completely different depending on the strategy.  This is the first thing that we should keep in mind. 

The other thing is considering the different strategies or the potential risks associated with each of them and then compare these potential risks with the risks of a planet that is becoming warmer and warmer in an unprecedented and very dangerous way.  Maybe the best tool we have up to now to analyze this issue is to compare the risks of a warming planet against the risks of solar radiation modification and other different strategies that we can think about.

I am glad that you raised the different kinds of approaches because sometimes I get a sense in articles or the public discourse people say geoengineering as if it is one thing, but of course it could be lots of different things. 

Similarly, comparing as you say the risks of SRM against the risks of a warming world, do you think the public debate is understanding these new answers or are we very much only at the beginning of how you actually go about explaining that, and do you think people are ready to engage in a more nuanced, complex way of understanding what you are looking at? 

I think it is to understand. We are trying to produce information about this risk framework, but we think the best way is to understand the potential impacts of SRM and compare them with those of climate change, and maybe it is the best tool we have to make a decision about if it is a good or bad idea or something that we still need to know more about to make a decision. 

I am sure that it is not easy to understand this because we have many uncertainties and we need to do more research to have more information about the potential risks of SRM.  We know more about the risks of climate change but not so much about the risks of SRM.

Let’s take one specific example, your work in La Plata.  Can you tell us how you see from your work the comparative risks of climate change on the region and the use of SRM in this hotter world in the region? 

We identify, for example, some benefits of a reduction in the extreme temperatures in the basin.  This is good because we have the city of Buenos Aires within the basin and lots of people living there and economic activity, so extreme temperatures are something that is dangerous for people and also for ecosystems and economic activity. 

The other thing is that we also explore potential changes in precipitation and in river flows, and what we found is that we can expect a reduction of extreme precipitation and also changes in river flows, for example, less frequent low flows, and this could also be a good or positive consequence of SRM.  We also found an increase of extreme flows, meaning high flows, which would lead more frequently to floods.  So for the same region we can expect some good results and some bad results but always compared to a high-emission scenario.  This is the first step.  To explore the potential impacts of solar radiation modification in the La Plata Basin, we need more research, but at least with these results we have this situation, some benefits and some increased risk in other parts of the basin, for example.  

We will talk a little bit later about how policymakers might use that kind of information. 

You said you are inspired by the need to learn more about how it would affect your region.  In general how important do you think it is for scientists across the Global South — Latin America, the Caribbean, and in other regions — to get involved in SRM research, and how much do you see that happening right now? 

It is very important to have scientists from the Global South being part of the conversation and doing research on SRM because the strategy of introducing aerosols into the stratosphere, stratospheric aerosol injection, can change the climate not only at the regional scale but on a global scale, so we must be part of this conversation because we are talking about a technology that can produce changes in different regions, and there is a need for a governance structure in that sense.  Our governments — the governments of the different countries in the Global South — need to be part of the conversation and to have information produced by local researchers.  I think it is relevant because we have the human resources to do this research.

I believe you received some funding for your work from the Developing Country Governance Research and Evaluation for SRM (DEGREES) Initiative.  What other kind of support is out there?  How much is funding a challenge for the Global South and scientists who would want to study this, given all the other things that could be funded? 

Also maybe we could touch on some other challenges in terms of access to computing or access to the right conferences, the right experts, and the right places.  I would love to learn a little bit more about what challenges you see facing potential Global South researchers on SRM. 

Funding is an issue for research in the Global South because as you mentioned there are lots of things that we need to know more about in our regions, including climate change.  To have funding from DEGREES is very relevant.  It was my starting point to do research on SRM, and after that I received funding from a national agency in Argentina, and the support of an agency from my country to do this research was important. 

Anyway, funding is limited when we need more computing and when we need to be part of different events and also to publish our research in journals.  That is usually very expensive.  In that sense we need more funding.  Of course, DEGREES was a starting point, but maybe larger funding from different agencies is good.  In this sense, DEGREES also helped Global South scientists network with scientists from the Global North with South-North cooperation and also South-South cooperation.  The North-South cooperation is good because in some ways it opens to us the doors to different funding and to cooperation with researchers from different institutions. 

SRM is pretty controversial, especially perhaps in the North.  I wonder to what extent some of the opposition increasingly expressed including by nongovernmental organizations (NGOs), scientists, and various others to SRM and all the various accusations — they say, “Oh, this is moving things away from what we should be doing, this is unnatural” — how much does that weigh on scientists?  How much of that is a problem?  How much does that put scientists off from doing this work?  I would be interested in how you have experienced that, especially perhaps from your experience in Latin America, where I have certainly seen a lot of skepticism expressed? 

It is not easy, not because other scientists are saying you should not be studying the potential impacts of SRM in this region but maybe more from NGOs or from people who clearly do not understand the meaning of our research and why we are doing this.  Sometimes it is not a very comfortable situation, but I think we can manage. 

The very strong idea is that what we are doing is exploring and trying to understand the potential impacts.  We are not saying we should do this, but what we are saying is that if somebody is going to do this, this is what could happen in this region.  In that sense I think we can manage the situation, and we have the support of the national research agency.  This is very important.

When you face criticism and you explain it in the way you just explained it — I am not saying we should do this; I am saying that we need to know what would happen in our area if someone did it — do you find that is something that critics accept, that makes someone go, “Okay, that is a good point?”  Are you seeing that people are meeting you on this? 

Sometimes yes and sometimes no because there are some radical positions related to this and they say solar geoengineering can be traced to what they see in the sky, and it is difficult to convince people that this is not geoengineering, which is not happening yet and this is something different.  In that sense it is easier to talk to other scientists and not so easy to talk to the general public but to people who have an understanding of the atmosphere and different climate processes.

Let’s move on to some of the UN processes.  You are one of the co-authors of UNEP’s One Atmosphere: An Independent Expert Review on Solar Radiation Modification Research and Deployment.  Notably it stated, “SRM is the only option that could cool the planet within years,” which is quite a bold statement, but it also said, “An operational SRM deployment would introduce new risks to people and ecosystems.” 

Perhaps you could take me through what you see as the report’s main recommendations and also talk a little bit about the reaction to that report. 

 The recommendations are that of course mitigation is the most important climate action.  We must reduce CO2 emissions into the atmosphere. 

Adaptation is also relevant when we consider climate action.  In some ways we are not on track to limit global warming under 1.5°C, so we need more research about these technologies.  We do not know enough to decide now. 

We identified that there are some benefits — for example, cooling the planet — but there are also some risks, and these risks are in some way associated to uneven distribution of the cooling effect.  It is a technology that could be over-effective in some regions, it may cool a region more than is needed, and in other regions it could be not enough.  It will create a new climate, and we do not know enough about how this new climate could be in terms of the consequences of this because it is not like a time machine going back to a previous climate that we already know, so we need to understand more about these risks.  We have little understanding about the potential effects on human health, for example, on ecosystems, or on water availability in different regions.  We know something about the La Plata Basin, but there are many important basins around the world that we need to understand more.  In that sense we do not know the risks yet and we need more research. 

Talking about research, this report also mentions that we need governance of research.   

There are different levels for governance of research.  For small-scale research, the research that we usually do with computer simulations, what we call “indoor” research we do not think we need a governance structure because there are codes of conduct for researchers and academic freedom related to this, so in that sense that is not necessary, but when we talk about “outdoor” research, even for small-scale local research, there was not full agreement within the group of authors of this report.  One of the ideas is that maybe the outdoor research would accelerate the deployment of this technology.  It is called a “slippery slope” idea.   

So there are different levels of discussion.  Obviously at the end if this is going to be used in an operational way, it would need a governance structure, but what was identified is that we need governance of the stratosphere, for example, when we think about introducing aerosols into the atmosphere.  These are some of the discussions involved with this report.

Where might some of that governance take place?  What bodies were suggested where that governance could happen? 

We do not really know, but it seems like the United Nations is in a good position to be part of this governance structure because it has the experience of working with all countries, but maybe this is something that should be discussed.  At the beginning, for example, the United Nations would be in a good position to start. 

Do you think the Intergovernmental Panel on Climate Change (IPCC) should be addressing SRM in more detail, and if so, how and where? 

Solar radiation modification is part of the report.  In the Sixth Assessment report there is a very large section related to this.  Scenarios considering SRM are not at the end part of the large assessment of the possible scenarios. 

I think this is a step that should be discussed.  I do not know what will happen, but it would be good considering the different Shared Socioeconomic Pathways (SSPs)or the different scenarios with different emissions of greenhouse gases.  Also these kinds of scenarios should be part of the same group of scenarios being discussed in the report, but this is a personal idea.  The SSPs were used in the last cycle of IPCC. 

Most recently UNESCO’s World Commission on the Ethics of Scientific Knowledge and Technology issued a report on the ethics of climate engineering, and it called for “the formulation of ethical values and principles.”  What might that look like in practice? 

There are six issues that should be considered related to the ethics of climate engineering.  At this point I want to mention that this report refers not only to solar radiation modification, but it also includes carbon dioxide removal. 

Different issues related to ethics are: 

(1) Governance. When we are talking about changing the global climate we need this governance structure; 

(2) Participation.  We need everybody to be part of this kind of conversation including the Global South and different groups — indigenous people, women, and young people. 

(3) Also there is a strong role for scientific knowledge and scientific community to be part of this conversation because we need to produce more information, we need more research, and we need research both from the physical sciences but also from the social sciences to be involved in this conversation; 

(4) We need to strengthen capacity.  Capacity building is another issue.  We need more researchers in different areas in this conversation. 

(5) We also need education because we need to communicate what we know and what we do not know and the potential risks and potential benefits that this technology may have. 

(6) The last point is related to awareness and how UNESCO could relate in some way the discussion about the ethics of the potential deployment of these technologies.

One thing that interests me about the ethics is that sometimes you are having a conversation between two people about SRM and you realize you are not connecting somehow.  The moment comes sometimes when you realize, Oh, we are using different ethical frameworks here.  Let’s say one person is using a framework of how to have the least suffering for the greatest amount of people and that is their measure of whether this is a good thing or a bad thing, and somebody else might be more driven by red lines — these are lines over which you cannot cross —– whether religious or to do with Mother Earth or whatever.  How do you deal in conversations when people are coming at this from such different ethical frameworks, from such different ways of analyzing the world? 

It is not easy, and it was hard during the preparation even of this report at this stage because we have people coming from different sciences and living in different regions, and the perception of climate change is also different from each other. 

I think this last year the extreme precipitation and temperature events and the scale of these unprecedented events in some ways is moving the line to a discussion.  Will we be able to live everywhere on this planet or are some places going to a climate where no one can live because of extreme temperatures, for example?  I think in that sense the unprecedented changes we have seen in climate during the last months are moving the discussion to the idea that there really is an emergency.  Maybe it is not the time right now to deploy these technologies — and even if we wanted, we cannot do it at the global scale — but it is time to think about it, to do more research, and in some cases to have these ready in case we need to use them in this generation or the next generation because we are not on track to live to the next generation in a very good way. 

There is so much more I would love to talk with you about — misinformation and the state of the science.  We could talk a lot longer, but I realize we are reaching the end of this. 

Perhaps I could ask a final question on a more personal level.  The very fact that we are discussing this idea — SRM, stratospheric aerosol injection — shows that we are in a very serious predicament.  No one would consider this if we were not.  Especially given the confusion out there and often misinformation and so forth it can be difficult as a scientist to stay optimistic and motivated, especially given the scale and the complexity of the problem and the apparent reluctance for powerful interests to get involved in solving it.  How do you get through that?  How do you find motivation?  Where do you get a sense of hope and energy from? 

I think the motivation is that maybe we have this technology that can help us to avoid the most dangerous aspects of climate change, to avoid overshoot or to reduce the overshoot for some time, and we can in some ways buy some time until we can really reduce emissions.  This is what motivates me, that maybe there is a temporary solution.  It is not the best solution probably, but maybe there is something there that can avoid the worst of climate change. 

Do you have a fundamental optimism and faith in human ingenuity to be able to work out its problems? 

We know the problem.  We know that humanity is responsible for the problem of climate change.  We know the solutions, and it is to phase out fossil fuels, but we are not doing that in the way and velocity that we need.  What we have now is at least this chance that maybe technology can help us for some time.  When you have kids and you want them to live in a better place I think you have the obligation to be in some way optimistic. 

Inés Camilloni, thank you so much for taking part in this C2GTalk.  It was really, really good.  Thank you. 

Thank you very much.