No. SAI is not a substitute for reducing greenhouse gas emissions. SAI does not address the root cause of anthropogenic climate change—the buildup of greenhouse gases such as carbon dioxide (CO₂), which persist for centuries, driving long-term warming, ocean acidification, and changes in extreme weather and climate. SAI may temporarily lower temperatures, but reducing greenhouse gas emissions significantly and quickly is essential for lasting climate stability and environmental health.

SAI is not intended to provide a comprehensive solution to climate change, but it might allow the necessary time for more permanent climate solutions and decarbonization to take hold.

No. Reflective supports expanding research in areas necessary for making informed decisions on whether and how to responsibly deploy SAI, when that time comes. We do not advocate for or against deployment, only providing the scientific evidence to support global, legitimate decision-making on climate-relevant timescales.

Our SAI Research Roadmap outlines a plan to build the needed evidence base for decision makers by defining which scientific questions must be answered, in what order, and at what cost.

Reflective is committed to conducting and funding research on SAI as part of the ecosystem of potential climate solutions, with a principled focus on objectivity, transparency, global collaboration, and responsible urgency.

We have built and maintained a number of tools for researchers, policymakers, and funders in support of SAI research. These include our Cloud Hub, an interactive cloud computing platform to support open, collaborative science for the SAI research community, and our SAI Simulator that provides a fast, interactive way to explore the climate effects of different SAI deployment scenarios and compare them to the impacts of continued warming.

We also publish the SAI Research Roadmap to coordinate research and optimize funding and resources for SAI. The Roadmap, along with our Uncertainty Database, identifies the most valuable and timely questions and the research required to reduce/resolve those uncertainties for responsible decision making on SAI.

Reflective also funds research projects around the globe that align with the priorities of the SAI Research Roadmap.

Stratospheric aerosol injection (SAI) is a proposed method to reflect incoming sunlight. SAI, which would involve distributing reflective aerosols, such as sulfates, in the lower stratosphere. These aerosols will reflect some sunlight into space, thereby decreasing the amount of heat that reaches the Earth. The idea is inspired by volcanic eruptions, which naturally send particles into the atmosphere, temporarily cooling the Earth.

Reflective focuses primarily on SAI for one reason: timeline. By 2030, we believe there will be demand for a rigorous assessment of a “first generation” approach to reflect sunlight, which we believe will be SAI using sulfate aerosols. Limited time demands focus and rigorous prioritization to reduce the most significant sources of uncertainty, to answer key open questions about the physical, societal and political risks and benefits, and to equip the world with the tools and technologies required.

SAI may be the most controversial climate intervention option, but (A) current research suggests that it’s the only approach likely to work as a tool for global, rather than more targeted, cooling, (B) it’s the most well-known method, so it’s going to be on the table once policymakers begin weighing options and (C) because there is a natural precedent for sulfate aerosols (stratospheric volcanic eruptions) that provides an upper bound on climate impacts at lower scales of deployment. Given this, we anticipate that sulfate aerosols are a likely “first generation” approach, with alternative aerosols a potential “second generation”.

While there can, and should, be effort put into research for “gen2” SRM approaches, these should only be funded once it is clear that activities on the critical path for “gen1” are adequately resourced and moving quickly.

The SAI Research Roadmap is a first-of-its-kind plan for the field, intended to coordinate research and optimize funding and resources to build the evidence base needed for responsible decision making on SAI. It provides a plan for the technical research needed to determine whether SAI is a tool the world could ever use responsibly to reduce global temperatures.

The Roadmap is built for policymakers, funders, and scientists, and shows how the field can narrow the most consequential scientific uncertainties step by step: from how reflective particles behave in the stratosphere to how different SAI strategies might affect the global climate. Research activities include a scientific justification, scope of work, estimated cost, and timeline, so funding and effort can be directed to the most valuable and timely questions.

Reflective is a nonprofit, funded entirely by grants or donations from a number of leading philanthropies focused on addressing climate change. We do not accept anonymous donations and transparently post a full list of our donors on our website. We also do not accept donations from corporations, foundations, or individuals if the majority of their current profits or wealth come from the fossil fuel industry unless they can clearly demonstrate that they do not have a conflict of interest and present a strong track record of supporting efforts to address anthropogenic climate change.

Email us at info@reflective.org or reach out to us from our contact page.