Optimal land supply for BECCS considering biodiversity conservation

Abstract: Bioenergy with carbon capture and storage (BECCS) will play a major role in mitigation pathways toward the 1.5º and 2ºC scenarios. Estimated land requirements for BECCS are big, ranging from 200 Mha-1500 Mha, for a deployment between 3-30 Gt CO2 per year in 2100. From where will the land be supplied to produce the additional biomass? What will be the biodiversity impacts of this land allocation? Current land allocation models used in Integrated Assessment Models (IAMs) do not consider biodiversity impacts when determining the location of the land for bioenergy. Here, we fill this gap by integrating a linear optimization model with a biodiversity impact assessment model, to determine how to optimally supply land to produce woody biomass for BECCS considering (1) minimizing biodiversity impact subject to a budget constraint, (2) minimizing cost subject to a biodiversity threshold and (3) fully omitting biodiversity. Initial results holding the amount of woody biomass constant, are that an allocation that minimizes biodiversity impacts obtains most (73%) of the additional land by reallocating already-human-modified habitats to give space for additional managed forests, whereas a model that minimizes the cost of land allocation obtains most of it (77%) from transforming natural habitats. The minimizing biodiversity impact perspective has a cost 13 times larger than the minimizing cost perspective, while the difference in species loss is small. A pareto frontier is constructed to indicate the trade-off between biodiversity loss and cost. This research addresses sustainable development goals (SDG) 13 and 15.