Solar Radiation Modification (SRM) may lower Southeast Asia’s extreme rainfall compared to the worst case scenario, with G6sulfur showing greater regional variability than G6solar. Information on future changes in precipitation is essential for guiding water resource planning and climate adaptation strategies. In this study, precipitation data are obtained from multi-model climate simulations conducted under the Geoengineering Model Intercomparison Project Phase 6 (GeoMIP6), which provides physically consistent projections of future hydroclimatic conditions in Southeast Asia (SEA). 

The simulations include both baseline emission scenarios (SSP245 and SSP585) and solar radiation modification (SRM) scenarios (G6solar and G6sulfur). For total precipitation amount, SSP585 scenario shows the strongest late-century increase, whereas SRM scenarios substantially suppress this amplification. Among the scenarios targeting SSP245-level radiative forcing, G6solar produces total precipitation patterns that are very close to SSP245, with only small positive anomalies in Maritime SEA. In contrast, G6sulfur exhibits much larger spatial variability, lowering total precipitation in Maritime SEA while increasing it in north SEA. Overall, G6solar maintains relatively stable basin-wide precipitation totals, whereas G6sulfur introduces more heterogeneous regional responses.

The precipitation change maps in this study were produced using annual total precipitation in wet days (PRCPTOT) from multi-model simulations under four future scenarios (SSP245, SSP585, G6solar, and G6sulfur). The relative changes are calculated for each year in 2020–2099 with respect to the historical baseline period (1995–2014), allowing the temporal evolution of precipitation changes to be assessed. Analyses are performed on the annual scale, reflecting long-term hydroclimatic shifts across Southeast Asia. The scenario ensemble includes both conventional warming pathways and solar radiation modification strategies, enabling comparison of their differing impacts on regional precipitation.

The baseline Shared Socioeconomic Pathways represent plausible future trajectories of greenhouse gas emissions: SSP245 describes a moderate-forcing pathway with intermediate mitigation efforts, while SSP585 represents a high-forcing pathway characterized by continued fossil-fuel dependence and rapid warming. In contrast, the GeoMIP solar radiation modification (SRM) scenarios simulate deliberate reductions in incoming solar energy to counteract greenhouse warming. G6solar applies a uniform reduction in total solar irradiance, whereas G6sulfur represents a stratospheric aerosol injection strategy that increases stratospheric sulfate aerosol loading to reflect sunlight. 

Together, these scenarios enable a systematic assessment of how both conventional emission pathways and hypothetical SRM strategies may alter regional rainfall regimes. All precipitation fields are provided at annual resolution and have been re-gridded to 0.25° × 0.25° covering Southeast Asia to ensure comparability among models.

Feng, Z. Q., Tan, M. L., Juneng, L., Tye, M. R., Xia, L. L., & Zhang, F. (2025). Effects of solar radiation modification on precipitation extremes in Southeast Asia: Insights from the GeoMIP G6 experiments. Advances in Climate Change Research, 16(3), 591-605. https://doi.org/10.1016/j.accre.2025.04.009