This Road Map Could Help Us Decide Whether to Deploy Solar Geoengineering
A new report from the nonprofit Reflective lays out the experiments needed to better understand our ability to dim the sun.
By James Temple | September 10, 2026
As global temperatures continue to break records in 2026, the debate over solar geoengineering—deliberately reflecting a portion of sunlight back into space to cool the planet—has shifted from the fringe to the mainstream. A new report from the nonprofit organization Reflective aims to bring clarity to that debate by outlining a detailed, step-by-step research agenda for the experiments needed to determine whether solar geoengineering is viable, and under what conditions it might be deployed.
The report, titled A Road Map for Solar Geoengineering Research, argues that without a coordinated program of small-scale, controlled experiments, policymakers will be forced to make decisions about deployment based on speculation rather than evidence. The authors stress that the goal is not to promote deployment but to generate the knowledge necessary for informed governance.
The Case for a Structured Research Agenda
Solar geoengineering—most commonly discussed in the form of stratospheric aerosol injection (SAI)—involves releasing reflective particles into the upper atmosphere to mimic the cooling effect of large volcanic eruptions. While computer models suggest this could lower global average temperatures quickly and relatively cheaply, the physical, chemical, and geopolitical uncertainties remain enormous.
"We are in a situation where some countries are already exploring unilateral deployment, yet we lack even the basic observational data to predict what would happen," said Dr. Elena Marchetti, lead author of the Reflective report. "A road map doesn't commit us to action; it commits us to understanding."
The report identifies three primary categories of experiments:
- Laboratory and modeling studies to improve our understanding of aerosol microphysics, atmospheric chemistry, and radiative transfer.
- Small-scale field experiments using high-altitude balloons or aircraft to release tiny quantities of inert aerosols and measure their behavior in the stratosphere.
- Monitoring and attribution research to detect the effects of any future deployment and distinguish them from natural variability.
Key Milestones and Timelines
The road map proposes a 10-year timeline, with the first phase (2027–2029) focused on laboratory work and the development of low-impact field experiment platforms. The second phase (2030–2033) would involve coordinated small-scale field campaigns, potentially under the auspices of an international research consortium. The final phase (2034–2036) would focus on integrating findings into policy frameworks and developing robust monitoring systems.
Crucially, the report emphasizes that no experiment should proceed without transparent international oversight, including mechanisms for informed consent from affected communities and clear exit strategies.
Beyond Science: Governance and Ethics
While the road map is technical in nature, Reflective acknowledges that solar geoengineering is not merely a scientific challenge. The report calls for parallel work on governance, ethics, and public engagement. It recommends the creation of an international advisory body to review proposed experiments and ensure that research does not become a slippery slope toward unilateral deployment.
"The decision to deploy, if it ever comes, must be made by societies, not by scientists alone," Marchetti added. "Our role is to reduce uncertainty so that decision can be made with open eyes."
What's Next?
Reflective plans to convene a series of workshops in 2027 with scientists, policymakers, and civil society groups to refine the road map. The organization also hopes to attract funding from both public and private sources to support the proposed research agenda.
As the climate crisis intensifies, the question of whether to dim the sun is no longer hypothetical. With this road map, Reflective offers a path to answer that question not with ideology, but with evidence.
Image: Stephanie Arnett/MIT Technology Review | Adobe Stock