The land-energy-water nexus of global bioenergy potentials from abandoned cropland

Bioenergy is a key option in climate change mitigation scenarios. Growing perennial grasses on recently abandoned cropland is a near-term strategy for gradual bioenergy deployment with reduced risks for food security and the environment. However, the extent of global abandoned cropland, bioenergy potentials and management requirements are unclear. Here we integrate satellite-derived land cover maps with a yield model to investigate the land-energy-water nexus of global bioenergy potentials. We identified 83 million hectares of abandoned cropland between 1992 and 2015, corresponding to 5% of today's cropland area. Bioenergy potentials are 6-39 exajoules per year (11-68% of today's bioenergy demand), depending on multiple local and management factors. About 20 exajoules per year can be achieved by increasing today's global cropland area and water use by 3% and 8%, respectively, and without production inside biodiversity hotspots or irrigation in water-scarce areas. The consideration of context-specific practices and multiple environmental dimensions can mitigate trade-offs of bioenergy deployment. Bioenergy from grasses is a key option to mitigate climate change. This study finds that recently abandoned cropland could help meet 11-68% of today's bioenergy demand.