PROJECTED DROUGHT RISK IN PAKISTAN UNDER SSP2-4.5 AND SSP5-8.5: AN INTEGRATED ASSESSMENT OF HAZARD, EXPOSURE AND VULNERABILITY

Abstract

Drought risk in Pakistan is shaped by the interaction of a changing climate with rapidly evolving socioeconomic exposure and uneven adaptive capacity. This study develops a spatially explicit framework to assess drought hazard, exposure, vulnerability and integrated risk across Pakistan for a historical baseline (1992-2015) and three future periods: 2026-2050, 2051-2075 and 2076-2100, under SSP2-4.5 and SSP5-8.5. Daily precipitation and temperature observations from 62 Pakistan Meteorological Department stations were combined with four CMIP6 global climate models (CNRM-ESM2-1, MIROC6, NESM3 and MRI-ESM2-0). Random Forest and SHAP were used to evaluate the relative contribution of the GCM inputs. Meteorological drought was characterized using the three-month Standardized Precipitation Evapotranspiration Index (SPEI-3), and drought frequency, duration and severity were integrated to represent hazard. Population density, GDP density and crop area represented exposure, while GDP per capita and channel density were incorporated as vulnerability-related capacity indicators. The results show a progressive increase in drought frequency, duration, severity and composite hazard from the near to the far future, with SSP5-8.5 consistently producing stronger conditions than SSP2-4.5, particularly after mid-century. Integrated risk is highest where climatic hazard coincides with concentrated population, economic activity and cropland. Punjab and Sindh emerge as the principal national risk hotspots; Sindh shows the most persistent increase relative to the historical baseline, while Balochistan becomes increasingly important toward the end of the century. Gilgit-Baltistan and parts of Khyber Pakhtunkhwa exhibit high physical hazard despite comparatively lower socioeconomic exposure. The findings demonstrate that drought planning based only on climatic hazard can misrepresent national priorities and that adaptation should jointly address water governance, early warning, urban water security, irrigation efficiency, groundwater management and region-specific resilience. The normalized indices developed here are intended for comparative spatial planning rather than probabilistic or monetary loss estimation.