Rainstorm Flood Risk Assessment in the China–Pakistan Economic Corridor Under Different Shared Socioeconomic Pathways of the 21st Century

Abstract

Global warming has intensified the atmospheric water cycle, leading to more frequent and severe extreme precipitation events, which are a major driver of rainstorm-induced flooding. Developing regions such as the China–Pakistan economic corridor (CPEC), spanning highly heterogeneous terrain and climate zones, face elevated risk due to limited infrastructure and preparedness. This study establishes a comprehensive flood risk assessment framework based on the Hazard–Sensitivity–Vulnerability–Adaptive Capacity (HSVA) model, integrating bias-corrected Coupled Model Intercomparison Project Phase 6 (CMIP6) multimodel precipitation, quantitative socio-environmental indicators, and Geographic Information System (GIS)-based spatial analysis. Applied to Shared Socioeconomic Pathway (SSP) scenarios SSP1–2.6, SSP2–4.5, and SSP5–8.5 for the period 2025–2100, the framework captures the spatiotemporal evolution of rainstorm flood risk. Results show a consistent intensification of extreme precipitation, with high-risk zones expanding northwestward along the Indus River corridor. Quantitatively, high-risk areas range from approximately 5% under SSP1–2.6 to over 6% under SSP5–8.5, indicating an upward trend under high-emission pathways. Model validation demonstrates strong agreement with historical flood records, achieving hit rates above 72% across all scenarios. These findings provide actionable insights for targeted flood mitigation, climate-resilient infrastructure planning, and sustainable water resource management in the CPEC region.