Why has the Brazilian Cerrado been left behind by voluntary environmental policies?

• Brazil’s biodiverse Cerrado biome is overlooked in environmental policies. • We analyzed the factors influencing conservation policy adoption in the soy supply chain. • Public awareness drove policy adoption in the Amazon but not Cerrado. • Empowered far-right politics constrained companies’ environmental policy adoption. • A policy window to adopt Cerrado conservation policy is now open. The expansion of soy production has been a deforestation driver in Brazil in both the Amazon and the highly biodiverse Cerrado savannah ecosystem. To tackle this problem the soy industry implemented a sector-wide zero-deforestation policy in 2006 in the Amazon called the Soy Moratorium. The Soy Moratorium sharply reduced the soy-driven deforestation in the Amazon. However, to date, despite substantial soy deforestation, the neighbouring Cerrado remains unprotected. Here we ask why no comparable zero-deforestation agreement was implemented in the Cerrado. To answer this question, we integrated theory on policy adoption and selection from the voluntary environmental policy literature with theory on policy process and feasibility from public policy, political economy, and organizational theory. This expanded framework enabled us to better understand how historical, political and geographical contextual factors shaped the differing policy adoption outcomes in the Amazon and Cerrado. We then conducted 26 in-depth interviews, including with key private sector decision-makers on policy adoption to understand the relative importance of different potential factors. We found that the differences in public awareness, national politics and narratives, changes in trade relationships, leadership and sunk investments influenced why an agreement emerged in the Amazon and not the Cerrado. Despite these circumstances, a new political window for Cerrado conservation policies has recently emerged with Brazil’s political shifts to a left-centre coalition and efforts to extend new due-diligence deforestation regulations to other wooded lands, including the Cerrado.