Solar geoengineering: Who wants to research, test or stop it?
Updated 7 October 2026
David Keith · Expand non-release research
He argues that SRM deserves serious scientific study and in 2026 called for public, transparent work on better methods and end-to-end system design. His support is for research alongside emissions cuts, not for immediate deployment.
David Keith · Allow small outdoor tests
He has explicitly argued for small atmospheric experiments and helped develop SCoPEx. His University of Chicago interview describes small releases as part of the research needed to understand SRM risks; the later cancellation of SCoPEx was not a rejection of field research in principle.
David Keith · Build deployment-ready capability
In April 2026 he argued that the field needs a technically detailed, public plan covering materials handling, aircraft dispersal, monitoring, data assimilation and controls for an initial SRM programme. He wants this capability developed transparently by public or non-profit research rather than by opaque for-profit firms.
Advanced Research + Invention Agency (ARIA) · Expand non-release research
Its Exploring Climate Cooling programme funds modelling, laboratory work, observations, social-science and governance research to build evidence about proposed climate-cooling approaches before any deployment decision.
Advanced Research + Invention Agency (ARIA) · Allow small outdoor tests
The programme includes small, controlled outdoor experiments where indoor work cannot answer the question, including cloud-reflectivity work using seawater and contained studies of candidate stratospheric particles. ARIA says effects must be small, temporary and reversible.
Advanced Research + Invention Agency (ARIA) · Build deployment-ready capability
Its dated programme materials frame the work as evidence-building and explicitly say ARIA is not funding deployment. Because the programme also studies technical feasibility and scalability, the reviewed dated sources do not cleanly establish whether every engineering component falls outside deployment-ready capability as defined here.
The Degrees Initiative · Expand non-release research
Its 2026 coordinated agriculture programme funds teams across developing regions and China to use common modelling protocols to study how SRM could affect crops. Degrees' research portfolio is centred on modelling and socio-political research rather than physical outdoor releases.
Environmental Defense Fund · Allow small outdoor tests
EDF argues that carefully designed, transparent small-scale field research can reduce uncertainty about solar geoengineering and that governance should develop from the first experiments. It separates this research stance from support for deployment.
Environmental Defense Fund · Back a deployment moratorium
EDF says deliberate albedo-modification interventions should not be undertaken for the foreseeable future. That is a clear anti-deployment position, but the reviewed policy statement does not itself advocate a formal national or international moratorium or non-use agreement.
Group of Chief Scientific Advisors to the European Commission · Expand non-release research
Their Scientific Opinion recommends an EU-wide research and assessment programme covering physical effects, risks, governance, ethics and justice while strengthening scientific capacity to inform future policy.
Group of Chief Scientific Advisors to the European Commission · Allow small outdoor tests
The Scientific Opinion recommends governance guidelines for outdoor SRM research and a moratorium on large-scale outdoor experiments. That leaves carefully governed smaller experiments possible, but it is a qualified rather than unconditional endorsement.
Group of Chief Scientific Advisors to the European Commission · Back a deployment moratorium
The advisers recommend that the EU adopt a moratorium on SRM use as part of its position and seek an international governance framework that prevents deployment unless future evidence and governance justify reconsideration.
Solar Geoengineering Non-Use Agreement · Expand non-release research
Its 2026 response says opposition to solar geoengineering need not foreclose legitimate scientific inquiry and acknowledges work such as improved modelling. At the same time, it rejects building a global programme that normalises or advances technological development, so support for expanding non-release research is qualified.
Solar Geoengineering Non-Use Agreement · Allow small outdoor tests
One of the initiative's five commitments is to ban outdoor experiments of solar geoengineering technologies. It argues that such experiments help institutionalise a technological trajectory before legitimate global governance exists.
Solar Geoengineering Non-Use Agreement · Build deployment-ready capability
The proposed non-use agreement includes commitments against public funding for solar-geoengineering technology development and against patents for such technologies, directly opposing the development of deployment-ready capability.
Solar Geoengineering Non-Use Agreement · Back a deployment moratorium
The initiative's core proposal is an international non-use agreement whose commitments include no deployment of solar geoengineering by states and no institutional support for its development or deployment.
African Ministerial Conference on the Environment (AMCEN) · Back a deployment moratorium
AMCEN Decision 20/Dec.9 calls for establishing a solar-geoengineering non-use agreement and for advancing the issue through a UN General Assembly resolution. The decision rejects promotion of solar geoengineering as a climate-mitigation solution.
Stardust Solutions · Expand non-release research
Its 2026 research principles describe modelling, laboratory work and non-dispersive research as core parts of responsible technology development before and alongside any outdoor atmospheric work.
Stardust Solutions · Allow small outdoor tests
The company argues that some key questions cannot be answered indoors and that carefully governed outdoor atmospheric experiments are therefore necessary, with staged testing, monitoring and transparent oversight.
Stardust Solutions · Build deployment-ready capability
Stardust explicitly frames its work as developing technology that could make SRM practical and controllable if governments and international institutions later choose deployment. That is deployment-enabling engineering even though the company says it should not decide whether deployment occurs.
Make Sunsets · Allow small outdoor tests
The company carries out real atmospheric sulfur-dioxide releases while also referring to localized-cooling work and measurement as experiments. Because those releases are intertwined with commercial Cooling Credit delivery rather than a research-only test regime, its fit with the narrow field-test category is qualified.
Make Sunsets · Build deployment-ready capability
Make Sunsets has published a scaling pathway using balloons and aircraft and continues developing sensing and operational systems for larger releases. Its engineering goal is explicitly to increase the quantity of cooling material deployed.
Make Sunsets · Back a deployment moratorium
Make Sunsets has explicitly argued that delaying deployment at scale is wrong and has continued selling and increasing sulfur-dioxide releases. That is directly incompatible with a moratorium on climate-scale deployment.
Sources
- University of Chicago Institute for Climate and Sustainable Growth — A radical solution to address climate change, with David Keith ·
- David Keith — Stardust is tackling the wrong problem with the wrong structure ·
- Advanced Research + Invention Agency (ARIA) — Exploring Climate Cooling | Programme thesis ·
- Advanced Research + Invention Agency (ARIA) — EIR026 – Information regarding outdoor experiments in the UK ·
- The Degrees Initiative — World’s first coordinated global study on solar radiation modification and agriculture launched ·
- Environmental Defense Fund — Our position on geoengineering ·
- European Commission: Directorate-General for Research and Innovation & Group of Chief Scientific Advisors — Solar radiation modification ·
- Solar Geoengineering Non-Use Agreement — Precaution Means Non-Use: A Response to UNEP’s Working Paper on Solar Radiation Modification ·
- African Ministerial Conference on the Environment — Decision AMCEN/20/Dec.9: Africa’s engagement at the seventh session of the United Nations Environment Assembly [Unedited Version] ·
- SSRN — Guiding Principles for Stardust's Solar Radiation Modification Technology Research ·
- Make Sunsets — Make Sunsets Monthly: Expanding ·
- Make Sunsets — Make Sunsets Monthly: Sensing ·
- Make Sunsets — How We Scale ·
- Make Sunsets — We Should Cool Earth ·
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