Miscanthus (Miscanthus × giganteus) and Willow (Salix spp.) are promising bioenergy crops due to their high biomass yields and adaptability to diverse climatic conditions. This study applies the MiscanFor/ SalixFor models to assess the sustainability of these crops under current and future climate scenarios, focusing on biomass productivity, carbon intensity (CI), and energy use efficiency (EUE). Under present conditions, both crops show high productivity in tropical and subtropical regions, with Miscanthus generally outperforming Willow. Productivity declines in less favourable climates, emphasizing the crops' sensitivity to environmental factors at the regional scale. The average productivity for Miscanthus and Willow was 19.9 t/ha and 10.4 t/ha, respectively. Future climate scenarios (A1F1 and B1) project significant shifts, with northern and central regions becoming more viable for cultivation due to warmer temperatures and extended growing seasons. However, southern and arid regions may experience reduced productivity, reflecting the uneven impacts of climate change. Miscanthus and Willow are predicted to show productivity declines of 15% and 8%, and 12% and 7% under A1F1 and B1, respectively. CI analysis reveals substantial spatial variability, with higher values in industrialized and temperate regions due to intensive agricultural practices. Future scenarios indicate increased CI in northern latitudes due to intensified land use, while certain Southern Hemisphere regions may stabilize or reduce CI through mitigation strategies. Under climate change, CI for Miscanthus is projected to increase by over 100%, while Willow shows increase of 64% and 57% for A1F1and B1, respectively. EUE patterns suggest that both crops perform optimally in tropical and subtropical climates. Miscanthus shows a slight advantage in EUE, though Willow demonstrates greater adaptability in temperate regions. Climate change is expected to reduce EUE for Miscanthus by 10% and 7%, and for Willow by 9% and 6%. This study underscores the need for region-specific strategies to optimize the sustainability of bioenergy crops under changing climate conditions.