CORDEX Ensemble-based drought projections for Sindh Province of Pakistan under climate change

Climate change threatens water-scarce regions significantly. This study utilized an ensemble of four CORDEX models to project droughts under climate change in Sindh Province, Pakistan, from 2011 to 2099, using 1981-2010 as the reference period. Droughts were analyzed under two representative concentration pathways (RCPs): 2.6 and 8.5. A distribution mapping approach was applied for bias correction against observed data from eight stations and the standardized precipitation evapotranspiration index (SPEI), which measures drought severity, was calculated at 6, 12, and 24-month timescales. Drought duration and severity were identified using run theory. Results indicate an overall decrease in SPEI, implying worsening drought conditions under both RCPs, with more severe droughts expected under RCP 8.5. The most significant declines in SPEI were noted from 2011 to 2040 under RCP 2.6 and from 2071 to 2099 under RCP 8.5. Hyderabad and MohenjoDaro exhibited the highest drought frequencies under RCP 2.6 (41 and 38%, respectively), while Rohri and Padidan showed the highest under RCP 8.5 (45 and 42%, respectively). The findings emphasize the urgency of adopting localized adaptation strategies to reduce escalating risks and impacts of prolonged and severe droughts driven by climate change.