Global hydropower potential affected by interplay between forest restoration and climate change

Forest restoration and hydropower production play a key role in mitigating climate change. However, they both depend on water availability, and influence the regional water distribution. It is therefore essential to understand how forest restoration affects hydropower potential under current and future climates. Here, we investigate these interactions on a global scale through an interdisciplinary approach using the Budyko framework. The analysis draws on cutting-edge datasets, including potential tree cover change, high-resolution climatic variables, and moisture recycling data. We assess the impact of regional and global afforestation scenarios on hydropower potential across current climate and future change scenarios (SSP1-2.6 and SSP3-7.0). While regional restoration generally results in a net negative impact on water availability (−13.4 mm yr⁻¹), global restoration helps mitigate this effect (−6.9 mm yr⁻¹). Similarly, global restoration yields more positive and fewer negative effects on hydropower potential compared to regional restoration. Future climate projections suggest a net positive impact on hydropower potential, though with more pronounced positive and negative effects at the dam catchment scale.  We stress that it is essential to consider the interaction between forest restoration and climate impacts on renewable energy systems, for the effective prioritization of forest restoration plans. Future research should focus on process-based models that better capture seasonal climate variability and account for feedback effects of restoration on moisture recycling. Furthermore, these models should integrate actual reservoir operations to accurately represent hydropower production within natural and physical constraints.