We can’t afford to stop solar geoengineering research

Last month, I attended the American Geophysical Union meeting in New Orleans, where 26,000 geoscientists convened in person and virtually to share the latest Earth and climate science. Maybe a hundred of those people were there to talk about research on solar geoengineering—the idea of reflecting a fraction of incoming sunlight to cool a warming planet.  

Contrary to popular belief, research on this topic is anemic; it has been more or less stuck for several years. I saw mothers with dark circles under their eyes presenting on Zoom to nearly empty conference rooms. Scientists from the National Center for Atmospheric Research on the mesa south of Boulder, Colorado, Zoomed in to share updated modeling scenarios; a few weeks later, NCAR would clock 90-mile-per-hour winds in a suburban firestorm that flattened surrounding neighborhoods. At the poster session, I saw the same woman I had seen at an AGU meeting five years ago, waiting to tell someone about her idea for preserving Arctic ice with reflective, hollow glass microspheres. Meanwhile, one aisle over in the Cryosphere area, people were jammed shoulder to shoulder—despite the pandemic—to hear about the collapsing “doomsday” glaciers.  

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This is the context of the International Solar Geoengineering Non-Use Agreement, proposed by a group of more than 60 senior scholars last week. 

A non-use agreement on solar geoengineering sounds great at first glance. Indeed, we should have a moratorium on the use of solar geoengineering, since the concept is so immature and theoretical; the science isn’t there to understand what reflecting sunlight would do to ecosystems, climate, or human systems. Nor is it a new idea: leading researchers proposed such a moratorium nearly 10 years ago in Science. We should also have a ban on patenting technologies, as suggested in this non-use agreement. 

The trouble with last week’s proposal is that it fails to adequately distinguish research from development or deployment. It’s a thinly veiled (or maybe not at all veiled) attempt to stifle research on the topic. Last year, the authors wrote a letter to Nature, objecting to an editorial titled “Give research on solar geoengineering a chance.” Their stance: “We call on our governments and funding agencies to halt the normalization of research into planetary solar-geoengineering technologies.” 

The non-use agreement doesn’t strictly prohibit “legitimate climate research.” Rather, it calls for a commitment to banning outdoor experiments and prohibiting national funding agencies from “supporting the development” of solar geoengineering technologies, both domestically and through international institutions. The non-use proposal further says that countries should “object to future institutionalization of planetary solar geoengineering as a policy option in relevant international institutions, including assessments by the Intergovernmental Panel on Climate Change.” So we would not be able to know how the foremost body of international scientists appraises the science. 

What is the real goal here? It’s not to build knowledge or encourage deliberation, but to make research unpalatable. The extended argument these authors published sketches out a vision where philanthropic foundations express their support for non-use and publicly declare not to the fund the development of solar geoengineering technologies. Universities, science associations, civil society organizations, parliaments, and more would also publicly support the International Non-Use Agreement. The result? “All of this would make such technologies increasingly unattractive for any serious research group to invest in, including in countries that might not immediately sign the international non-use agreement.”  

In other words, the idea is to create such intense social pressure that no serious research group would want to spend time on solar geoengineering for fear of criticism. Philanthropies and government agencies would hesitate to fund such research for the same reason.  

That would be a problem, because solar geoengineering might actually have significant benefits. Solar geoengineering could substantially offset global temperature rise and potentially offset serious secondary impacts, such as reduction in crop yields and increased frequency and intensity of hurricanes and typhoons. We don’t know everything about what it would do. But there is a strong humanitarian case for learning more, even if learning more reveals that the downsides outweigh the benefits. 

Intense social pressure to cease solar geoengineering research won’t mean that all such research will end—it means that researchers who care about openness and transparency might stop their activities, and the ones who continue might be less responsive to public concerns. They will be supported by funders that don’t care about public opinion—perhaps private actors or militaries—and we might not hear about all the findings. Autocratic regimes would be able to take the lead; we might have to rely on their expertise in the future if we’re not successful in phasing out fossil fuels. And scientists in developing countries—already disadvantaged in terms of participating in this research—may be even less able to do so if international institutions and philanthropies are not providing funds.  

Solar geoengineering research needs public funding through national science agencies. This can help ensure several important things. It can maintain public oversight of the research and enable the design of research programs where social scientists and governance scholars are integrated from the outset, producing the critical type of interdisciplinary research this topic demands. What’s more, public funding can be designed to encourage international scientific cooperation. For example, a paper presented at AGU that looked at the impacts of solar geoengineering on crop yields included researchers from Norway, the US, South Korea, and China. We want to continue this kind of cooperation, not stifle it. 

Perhaps most important, national funding agencies can structure research programs to examine the potential risks and benefits in a comprehensive way, making sure to give full attention to everything that could go wrong. Without this systematic approach, what gets published may be a trickle of studies showcasing only the most stellar results, making solar geoengineering look better than it is. Is that study about crop yields good? What does it miss? To find out the answers, we need more studies, not fewer, and we need bodies like the IPCC to assess them all together. 

No scientist is happy about the prospect of solar geoengineering. But we are going to need a pipeline of thoughtful, experienced people who understand both the science and the governance issues. If we disincentivize people from developing that expertise, we may not like the results. 

Good science takes years to develop. If we put off research until the 2030s, we could find ourselves in a world that’s made some uneven progress on the reduction of greenhouse-gas emissions but not enough, with temperatures still headed toward 3 °C of warming. We can’t then suddenly hope to produce rigorous science that would help us understand whether solar geoengineering is advisable. For a start, the US should follow the well-thought-out recommendations set up by the National Academies of Sciences, Engineering, and Medicine committee that recently grappled with this, and fund a modest, careful research program now. 

Holly Jean Buck is an assistant professor of environment and sustainability at the University at Buffalo and the author of Ending Fossil Fuels: Why Net Zero Is Not Enough

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