Evaluating future climate-driven changes in agricultural water resilience: Insights from CMIP6 model simulations for the Kagera River sub-basin

Abstract

Climate change poses a major threat to the availability of agricultural water in many regions of sub-Saharan Africa. This study evaluates the future climate-driven changes in the resilience of agricultural water (AgWater) in the Kagera River sub-basin, Tanzania. Climate projections were derived from CMIP6 muti-model simulations, while the Hydrologic Engineering Center Hydrologic Modeling System (HEC-HMS) was used to simulate the impact of climate change on river flows. The initial resilience evaluation system comprised of 94 indicators representing exposure, sensitivity, and adaptive capacity, which were screened to 66 indicators using a correlation matrix method. Indicator weighting was determined using two objective methods (entropy and CRITIC), and one subjective method (grey relational analysis). The results revealed significant future changes in both climate and hydrological regimes in the sub-basin, along with notable shifts in climate and hydrological extremes. The projected hydro-meteorological changes are expected to significantly impact the resilience of AgWater. The baseline resilience score of 0.38 is expected to increase to between 0.49 and 0.60 by the 2050s, with further increases ranging from 0.48 to 0.57 by the 2070s, and from 0.48 to 0.55 by the 2090s. Therefore, climate-driven changes are expected to positively impact the resilience of AgWater. These findings are crucial for informing adaptation strategies and policy development to enhance agricultural production in response to the impacts of climate change.