Biodiversity conservation policies alter the solution space of climate mitigation scenarios

Jan Steinhauser , Keywan Riahi, Sreyam Sengupta, Jan Philipp Dietrich, Florian Maczek, Patrick von Jeetze, Oliver Fricko, Di Sheng, Florian Humpenöder, Volker Krey, MIchael Obersteiner, Alexander Popp

Conserving biodiversity while mitigating climate change is one of the defining sustainability challenges of this century. Paris-aligned mitigation pathways rely heavily on forest restoration and bioenergy with carbon capture and storage (BECCS). While forest restoration can simultaneously enhance wildlife habitat and increase carbon sequestration, large-scale biomass production for BECCS may intensify land competition and conflict with biodiversity conservation goals. Here, we use an interlinked land-use (MAgPIE), energy (MESSAGEix), and climate (MAGICC) modeling framework to explore the synergies and trade-offs between biodiversity conservation and climate mitigation. We find that sustainable bioenergy potential compatible with ambitious biodiversity conservation targets is below 100 EJ/yr, limiting late-century carbon removal through BECCS in 2 °C scenarios to less than 6 GtCO₂/yr. At the same time, ambitious biodiversity conservation can approximately double carbon sequestration in forest systems. Our results show that Paris temperature goals remain achievable under ambitious biodiversity targets and that peak temperatures are lowered as much as 0.2°C compared to Paris-aligned scenarios without biodiversity targets, although doing so requires earlier and more stringent decarbonization.