Climate and ecological constraints of cultivating bioenergy crops for climate mitigation in tropical regions

Negative-emission approaches, such as bioenergy with carbon capture and storage (BECCS), are expected to play a crucial role in mitigating climate change. However, the capacity for biological carbon sequestration under changing climatic conditions remains highly uncertain, particularly in historically warm regions. Although bioenergy can be derived from various biological materials, nearly all operational BECCS facilities capture CO₂ from bioethanol fermentation. We therefore assess the share of bioenergy crop cultivation that will be exposed to future climate conditions beyond their historically safe climate space (SCS), focusing on tropical regions. We find that 30.5 to 40.3%, 10.4 to 13.0%, and 7.4 to 10.2% of existing oil palm, sugarcane, and soybean production will occur in locations surpassing the SCS of these crops by 2060 under lower warming scenarios. If farmers are unable to adapt effectively to emerging climatic conditions, the carbon sequestration capacity of bioenergy crops in tropical regions could substantially decline under the 2 °C warming target, with reductions of up to 67% for oil palm. However, if farmers instead overcome climatic constraints and expand cultivation in the tropics, conversion of land with an average aboveground carbon storage of around 0.45 Tg C per 100 km² and roughly 600 individual species per 100 km² would result in substantial reductions in ecosystem carbon and biodiversity losses that could outweigh the climate benefits of biofuel-based mitigation.