Letters to the Editor – August 2026

Professionals working on solar radiation modification (SRM) frequently talk about public engagement, for good reasons. Yet, what do we mean by public engagement? Usually, it suggests professionals reaching out to non-professionals.

In our systematic review of letters to the editor or correspondence on geoengineering, which includes SRM as well as other techniques, we found that a third of all letters were written by non-professionals. Social scientists and policy experts also wrote a proportionately high amount of letters.

This suggests that letters provide a unique kind of engagement that places a range of publics including non-professionals in an active position, and we invite SRM360 and other similar publications to offer a free (to publish and read) letter forum to improve public engagement on this important topic.

Timothy Daly
Researcher, FLACSO Argentina
Jaime A. Teixeira da Silva
Independent Researcher
Serhii Nazarovets
Senior Researcher, Borys Grinchenko Kyiv Metropolitan University

I enjoyed your recent article “Beyond the Ban” and would like to offer two additional thoughts regarding US state regulation of SRM. First, the drive to adopt bans at the state level appears to have peaked, which makes the model legislation proposed by Hester and Segall, though well-crafted, not quite as politically salient as it otherwise might have been. Second, regulating SRM seems more appropriate at the federal level than the state level, which calls into question a potentially disproportionate focus on the latter (especially when the pace of state-level activity appears to be declining).

There is an obvious risk of a patchwork of different state-level regulatory systems generating confusion and impeding research. A better path may entail working to develop model legislation – perhaps based on this new report – specifically designed for the federal level.

Joshua Horton
Senior Consultant, University of Chicago

In a perfect world, the United States would have a robust national research program on climate risks and potential responses, including the ability of the federal government to regulate private sector activity related to climate interventions so as to promote transparency and responsible scientific inquiry. Ideally, the U.S. program would serve as a model for other countries and jurisdictions and otherwise put the United States in a leadership position on a critical set of issues. Failing that, legislation at the state level could be a useful halfway house, provided it facilitates rather than impedes responsible research.

In this regard, Tracy Hester and Craig Segall’s white paper usefully demonstrates that one can find a healthy middle ground between blanket prohibitions and no regulation at all: one that puts guardrails on private actors while allowing legitimate research to proceed under public oversight.

Susan Biniaz
Former US Deputy Special Envoy for Climate
Dan Bodansky
Professor of Law, Arizona State University

In response to “Beyond the Ban: A New Model for US State SRM Bills”

SRM360 recently produced a “Brief History of Solar Geoengineering”. I liked this piece very much: clear presentations, and links are provided for those who wish to dig deeper.

One can always discuss why one entry was included when another one wasn’t. It is impossible to get this “right”. Nevertheless, I would have included at least the following:

• The IPCC held an Expert Meeting on Geoengineering in Lima, Peru, from June 20–22, 2011. It produced a meeting report that fed into the IPCC’s Fifth Assessment Report (AR5) treatment of solar radiation modification and carbon dioxide removal.
• The UN Environment Assembly (UNEA) has twice attempted but failed to adopt a resolution on “geoengineering” (2019 and 2023). This is significant, because this was the first time such a draft resolution was on the agenda of an intergovernmental process.
• A consortium of international NGOs convened a meeting of experts in London in July 2026 to contribute to the development of a Solar Geoengineering Research Governance (SGRG) process.

Janos Pasztor
Former Executive Director, Carnegie Climate Governance Initiative

During my childhood, at the height of the Cold War, the primary existential threat was nuclear weaponry. Today, climate change poses a far graver threat to younger generations – so much so that policymakers, engineers, and scientists are increasingly considering cooling the planet by deliberately modifying solar radiation (SRM). In a recent article, G. Davies examines arguments against SRM research and contends that the fear of SRM working “too well” leads some to worry it might hinder necessary societal transformations.

I agree with Davies that the main criticism leveled against SRM concerns neither its technical feasibility nor its limited effectiveness. Rather, SRM symbolizes the perpetuation of a world we would like to leave behind: an air-conditioned technological world that may seem safe to many but proves uninhabitable for numerous species (though, global warming is not the primary cause of the ongoing mass extinction) and inequitable for a growing segment of humanity. SRM is a dangerous technology precisely because it does not prompt us to rethink our relationship with the economy and with life itself. That is why it may represent a “moral hazard” even more pronounced than that of nuclear weapons.

Hervé Douville
Senior Scientist, Météo-France

Gareth Davies’ Perspective argues that the only rational response to much of the criticisms of SRM is more research. But his arguments lean too heavily on abstract ideological divides, portraying critics as enthralled by an “anti-capitalist” revolution, “new global order”, or “utopia” (the author’s terms in the related academic article) rather than engaging their actual concerns.

What underlies much of this criticism, in my reading, is not fear that SRM might work, but that the process for judging whether it “works” – whose knowledge counts, who gets to evaluate the risks, how closed the decision-making circle is – will be riddled with unfairness and exclusion. Re-casting such concerns as ideology only poisons the well further, undermining the discussion the author claims to want.

The greater risk isn’t whether SRM might work, but our tendency to take sides, caricature legitimate concerns, and leave no room for constructive discussion.

Chad M. Baum
Assistant Professor, Aarhus University