Protecting tropical forests is more cost-effective for biodiversity and climate than restoration

Halting deforestation and promoting restoration are at the core of strategies to confront the biodiversity and climate crises in tropical forests. Avoiding forest disturbances is also critically important but has received far less attention, and there is a lack of clarity about the relative cost-effectiveness of these three interventions. We compare the biodiversity and carbon benefits and costs associated with each intervention, comparing observed and counterfactual outcomes based on in-depth field assessments and high-resolution remote sensing in the Brazilian Amazon deforestation frontier. Avoidance interventions delivered the greatest benefits and were more cost-effective than restoration, with results being robust to a range of benefit and cost assumptions. However, combined interventions delivered the greatest gains and were essential to reverse biodiversity and carbon losses.