Impacts of Solar Radiation Modification on Extreme Climate Indices in the Philippines

The increasing global temperature and changing climate patterns have amplified the frequency and intensity of extreme heat events, droughts, and heavy precipitation, significantly impacting agriculture, water resources, and ecosystems. Solar Radiation Management (SRM) has been proposed as a geoengineering strategy to mitigate these effects by reducing incoming solar radiation. This study evaluates future trends and variability in rainfall and temperature extremes in the Philippines under GeoMIP (G6Solar and G6Sulfur) and ScenarioMIP (SSP2-4.5 and SSP5-8.5) projections. Using five General Circulation Models (GCMs) and a suite of 10 climate indices recommended by the Expert Team on Climate Change Detection and Indices (ETCCDI), changes in extreme precipitation and temperature across different climate zones in the Philippines were assessed. Climate projections for future (2041–2070) scenario are analyzed using bias correction, downscaling, and spatial interpolation techniques. Trend analysis is conducted using the Mann-Kendall test and Sen’s slope estimator, while variability is assessed through statistical methods. Results indicate a significant increase in extreme precipitation events and warming trends, with differences in SRM and non-SRM scenarios. These findings provide critical insights into the potential impacts of SRM on future climate extremes in the Philippines, for crafting potential adjustments and climate policy recommendations for stakeholders.