Reforming a pre-existing biodiversity conservation scheme: Promoting climate co-benefits by a carbon payment

Protecting forests provides potential synergies for both biodiversity conservation and climate change mitigation. Payments for ecosystem services (PES) schemes are commonly used to promote biodiversity conservation in private forests, and including carbon as another target may be a cost-efficient way to promote both goals. We analyse a hypothetical reform on a forest biodiversity PES scheme by supplementing it with a carbon payment paid to landowners for also providing carbon benefits. With a site selection model, we examine how the proposed scheme could promote biodiversity and carbon values, and what level of the carbon payment would provide the highest synergy gains. We found that introducing the payment promotes both targets, but there is a temporal trade-off between selecting sites with high carbon storage or sites with good sequestration potential. The highest synergy gains are obtained in most cases by a second-best payment level of 10-20 € tCO₂^-1.