The University of Chicago’s Climate Systems Engineering initiative (CSEI) has received a $5 million grant from Quadrature Climate Foundation (QCF) to support research into solar radiation management (SRM)—also known as sunlight reflection methods or solar geoengineering. The three-year grant aims to reduce uncertainties surrounding the scientific, engineering, and economic practicalities of sulfate aerosol-based SRM.
Established in 2019 by the founders of Quadrature Capital, QCF is an independent charitable foundation committed to combating climate change and the systemic injustices that drive climate vulnerability, including supporting solutions that reduce climate impacts, lift people out of vulnerability, and help communities adapt to a changing world.
“Despite decades of warnings, emissions are still rising, and climate impacts are intensifying. People are already suffering the consequences and those are going to worsen in the next decades. In that context, we need rigorous and transparent research to understand both the risks and the potential of approaches like solar radiation management. Our support for CSEi and its partners aims to strengthen the global evidence base and contribute to oversight structures that ensure any decisions are transparent, equitable, and grounded in evidence,” says Greg De Temmerman, Deputy CEO and Chief Science Officer, Quadrature Climate Foundation.
The foundation’s support will enable a collaborative effort led by CSEi, working with researchers from the University of Chicago, Colorado State University, Harvard University, the University of Hawaii, the University of Illinois at Urbana-Champaign, and partners at key engineering firms.
Stratospheric aerosol injection (SAI)—a form of SRM that involves releasing tiny reflective particles of sulfate into the stratosphere to reflect a portion of sunlight back into space—could significantly reduce climate risks in many regions. However, key questions remain about its practicality, effectiveness, and potential trade-offs.
“Funding from QCF enables us to take a detailed look at the practical engineering and policy questions around SAI-based SRM,” says David Keith, Geophysics Professor at the University of Chicago and Faculty Director of CSEi.
These questions include: What do current models really say about the benefits and risks of SAI? How long might it take to build planes that can deliver aerosols to the tropical stratosphere? What kind of aircraft might work? How do aerosols form in aircraft plumes? And how best to monitor the stratosphere?
QCF’s funding will support research across four workstreams:
- Assessing aircraft options for delivering aerosol precursors into the stratosphere. This includes evaluating new-build aircraft using both established and novel technologies, retrofitting existing aircraft, and examining the logistics of sulfur handling, transport, and certification pathways.
- Reducing uncertainty surrounding how aerosol particles form in the wake of aircraft. This workstream will use multiscale modeling and advanced parameterization to better understand the size distribution and behavior of aerosols immediately after being released.
- Exploring ways to increase the world’s ability to monitor aerosols in the stratosphere. This includes fostering dialogue between SRM researchers and experts in stratospheric science, as well as supporting an engineering study of a new monitoring technology that utilizes a constellation of microsatellites designed to measure aerosol concentrations using solar occultation.
- Evaluating the efficacy of SAI and its possible consequences. This workstream will rigorously evaluate current models to quantify the effectiveness of SAI, identify regions where it may be least effective or even counterproductive, and examine the limitations of existing research. A central goal is to ensure that the next IPCC report — expected in 2028 — more accurately reflects the consensus and uncertainties surrounding SAI.
SRM is not a substitute for cutting greenhouse gas emissions, but it could serve as a complementary tool alongside traditional climate mitigation. By clarifying the scientific and engineering feasibility of SAI-based SRM approaches, CSEi and its partners aim to inform future policy and research decisions with stronger evidence.
“This research will help the global community better understand what SAI-based SRM can and cannot do,” Keith says. “That understanding is essential for navigating the ethical, political, and technical dimensions of this potential climate intervention.”