Projecting potential evapotranspiration under climate change scenarios using the LARS-WG model in the Lake Ziway Watershed, Ethiopia

This study aims to project potential evapotranspiration (PET) in Ethiopia's Lake Ziway Watershed using the ensemble means of five CMIP5 GCMs for the 2050s under the RCP4.5 and RCP8.5 scenarios using the LARS-WG model. LARS-WG's calibration and validation results show that the model can generate future climatic data. PET's future projection was based on the LARS-WG model's forecast of future temperatures. The results revealed that the increment in PET under the scenario of RCP8.5 is higher than RCP4.5. Monthly PET is expected to rise from 5.70% to 18.09%, with the smallest in October and the largest in May. Its increment is most noticeable in the spring. PET is projected to rise by up to 15.70% as the annual mean temperature rises to 2.04 degrees C. Future climate change projections could have a significant impact on PET, which influences the water cycle and could pose a drought risk in the research area.