Assessing climate change impacts on the WEF nexus: A case study of water availability, thermal energy production, and rice yield in the Kangsabati river basin

• An integrated approach using CMIP6 data, a crop model, scenario-based empirical energy model and an indicator-based WEF nexus model was applied • The WEF nexus indices were forecasted for 2031 to 2091 at a decadal time step under SSP245 and SSP585. • WEF security in the basin will decline significantly under future climate scenarios. • The study proposes policy-level interventions to mitigate adverse climate impacts on WEF security. Climate change significantly impacts the water-energy-food (WEF) nexus because the WEF nexus's components naturally fluctuate due to dynamic changes in climate variables. The present study analysed the impact of climate change on water availability, thermal energy output, and rice yield in the Kangsabati River basin using CMIP6 data, and the basin's WEF nexus using a newly developed WEF Nexus model. The WEF nexus model has been developed using the Modified Pardee Rand indicator–based approach, which primarily uses secondary data for the analysis, except climatic data like rainfall and evapotranspiration. We initially analysed the WEF nexus for 2011 and 2021, and then based on the decadal change, we projected different inputs of the WEF nexus model except for climate data, rice yield and thermal energy production (examined from EC-Earth3 GCM, AquaCrop and scenario-based empirical energy model, respectively). We used the WEF nexus model to forecast the WEF nexus for 2031 to 2091, at a decadal time step, under SSP245 and SSP585. Results indicate that the annual average precipitation in the near-future will likely be higher in SSP245 than in SSP585. Under SSP245 and SS585, the basin's actual evapotranspiration will increase by 3.70–8.20%, while thermal energy production will decline by 0.21–2.42%. Furthermore, SSP245 forecasts a 10-15% drop in paddy output during Kharif (June–September) and 15–20% during Rabi (October–December), while SSP585 forecasts a higher decline of 15–20% and 20–25%. The study also reveals that the Water, Energy and Food Sub-indices, and WEF Nexus Index of the basin will decline by 42.33%, 1.67%, 7.67% and 19.33%, respectively, under SSP245, and 25.67%, 4.67%, 8.67% and 11.33%, respectively, under SSP585 in 2091 compared to 2021. This study provides recommendations to achieve SDGs 2, 6, and 7 targets by mitigating the impact of climate change on WEF security.