Solar radiation management (SRM) refers to a group of proposed climate change interventions designed to reflect a small fraction of incoming sunlight back into space to reduce global warming. Among these approaches, stratospheric aerosol injection (SAI) with the main idea to inject aerosol particles into the stratosphere by e.g. airplanes to scatter solar irradiance back to space (see Figure 1), has recently attracted growing scientific and public attention. While some view SAI as a possible emergency measure to complement emissions reductions, others raise concerns about governance, unintended environmental consequences, and questions of fairness across regions and generations. Understanding the physical and societal implications of such interventions is therefore increasingly important.
This study investigates how different SAI scenarios including sulfuric acid as liquid particles and diamond, calcite and alumina as solid particles could influence the amount of solar radiation reaching Earth’s surface under cloud-free conditions and explores potential implications for solar energy production. Because solar photovoltaic (PV) systems depend directly on incoming sunlight, even modest changes in surface solar radiation could affect future energy generation.
To quantify these effects, we performed benchmark radiative transfer simulations using the libRadtran model. The model was set up so that we can mimic the exact atmospheric conditions at a meteorological measurement site in Paris (Sirta). This was done to incorporate ground-based pyrheliometer measurements of solar irradiance and enable evaluation of the model. Atmospheric conditions were based on location-specific data from Earth observation platforms such as the Copernicus Atmosphere Monitoring Service (CAMS). On top of that, the hypothetical SAI scenarios as described above and depicted in Figure 1 were considered. In addition to horizontal surface irradiance results, we also tested the influence of PV panel tilts and orientations on the corresponding SAI scenario.
Our results indicate that, for moderate sun elevations, direct surface solar radiation decreases by approximately 3–12% across the investigated SAI scenarios. The reduction tends to be stronger for solid aerosol materials and becomes more pronounced when the sun is lower in the sky. At the same time, diffuse radiation reaching the surface increases substantially — by around 40% on average. Diffuse sunlight can penetrate more evenly through plant canopies and may enhance photosynthetic efficiency under certain conditions, highlighting that changes in solar radiation can affect not only energy production but also ecosystem functioning. These changes suggest that SAI would not simply reduce total sunlight but also alter its distribution between direct and diffuse components.
The generated radiation datasets will be used in follow-up simulations of PV electricity production for different solar technologies. Overall, this work provides insight into how proposed climate intervention strategies could influence renewable energy systems and highlights the importance of evaluating potential trade-offs between climate response measures and future energy supply.