Improved human development index may mitigate drought risk under the changing climate and socio-economic conditions

Drought is a recurring hydroclimatic hazard that significantly affects water resources, ecosystems and economic activities. Its overall risk is influenced not only by climate change but also by evolving population exposure and socio-economic vulnerability. This study develops an integrated framework to construct the Relative Drought Risk Index (RDRI) by integrating hazard with time-varying vulnerability and exposure. With the developed framework, the relative contributions of climate change and socio-economic conditions to drought risk are investigated. Drought hazard is quantified through the Standardized Precipitation Evapotranspiration Index (SPEI). Vulnerability is quantified using the Human Development Index (HDI), with values subtracted from 1, so that higher values correspond to higher vulnerability. Exposure is represented by population density of a grid. Both of these indices are time-varying and contrast this study with previous studies that are mostly based on a time-invariant approach. Considering the entire Indian mainland that spans across a wide range of climatic and socio-economic conditions, the developed framework is applied for the period 1991 to 2015. It is found that drought risk is higher in the Indo-Gangetic plain, eastern and north-eastern India compared to other parts of the Indian mainland. The findings reveal the combined role of frequent droughts, dense population, and low HDI in identifying high-risk regions compared to others. Temporal analysis reveals a clear spatial shift in drought risk between 1991 and 2003 and 2004–2015, with an overall reduction across 80% of regions, but intensified risk in eastern Uttar Pradesh, Bihar, and Madhya Pradesh in the later period. Notably, southern India shows a decline in risk, despite experiencing increased drought frequency, primarily due to improvements in socio-economic conditions. The analysis to investigate the relative contributions of climate and socio-economic conditions to drought risk change reveals that, in areas with rising drought risk, climate change and socio-economic conditions contribute approximately 73% and 27%, respectively. On the other hand, in regions where risk has decreased, the contributions are approximately 34% and 66%, indicating a higher contribution from socio-economic conditions. These findings indicate that socio-economic development can substantially reduce drought risk, underscoring the need for region-specific, hotspot-targeted development strategies to manage drought risk.