Projected Climate Change Impact Assessment on Drought Characteristics Over a Humid Tropical Region in India

Droughts are the major natural disasters affecting water availability leading to social, economic, and environmental challenges. Due to climate variability, investigation of climate change impact on droughts is of vital importance for sustainable societal and ecosystem functioning.  Western Ghats, a humid tropical region of India is selected as a case study to investigate the change in drought characteristics subjected to future climate change. In the last few decades, due to monsoon failure, the intensity of droughts has been identified to increase in this region making this study important. For future climatic variables, the ensemble of five Global Climate Models (GCMs) in the Coupled Model Intercomparison Project (CMIP5) are considered for the Representative Concentration Pathways (RCPs) 4.5 and 8.5. Standardized Precipitation-Evapotranspiration Index (SPEI) for the 12-month accumulated period is considered to assess the change in the drought characteristics during near (2011–2040), mid (2041–2070), and far future (2071–2100). The results indicate an increase in drought events in the future with maximum change during the far future for both RCP 4.5 and 8.5 scenarios. The major areas affected are in the southern part of Kerala and Karnataka. The change in total severity and duration of these drought events are high during the near future, moderate during the mid-future, and very high during the far future in both scenarios with RCP 8.5 being more severe. The findings show the variability in drought characteristics both spatially and temporally across the study area. The results will be helpful in identifying the hotspots prone to drought risk. This will serve as important guidance in improving the identification of causes, minimizing impacts, and enhancing the resilience to droughts in the study area. Further, the important implication of the study will be for water resource planning and management to strategize policies that emphasize on providing water in water-scarce regions during extreme drought situations.