Summary
Agricultural expansion is the main driver of forest and biodiversity loss. As a countermeasure, Voluntary Sustainability Standards (VSS) try to enhance sustainability in agricultural production but evidence if VSS reduce deforestation at country level is lacking. We used annual certification data of seven VSS (Fairtrade, Rainforest Alliance, UTZ, 4C, Round Table on Sustainable Palm Oil (RSPO), GlobalGAP, Organic) certifying five food commodities (cocoa, coffee, tea, palm oil, banana) and data on tree cover loss in humid tropical primary forest to study the impact of VSS on primary forest loss in 67 tropical countries. Using two generalised additive models (GAMs), one with VSS separately and one with VSS coverage aggregated, we found only Fairtrade to coincide with lower tree cover loss in primary forests at country level while we observed higher tree cover loss with higher certification for UTZ, RSPO and Organic. Using spatially explicit certification data in Google Earth Engine, we did not observe an effect of VSS on tree cover loss, thereby raising doubts on the potential of VSS to govern deforestation free supply chains. Reasons for this might be, among others, certification displacing unsustainable agriculture to other regions (leakage), weak or insufficiently enforced VSS criteria, and outcomes being context specific depending on, for example, institutional factors.