Highlighting the urgent need to restore the policy focus on 'sustainable intensification' in agriculture, and to develop science-based sustainability metrics capable of objectively and consistently monitoring the balance between resource use and environmental impact per unit of production. Robust farm-level metrics will provide the basis to define 'sustainable intensification' in practice, to set targets, measure progress and frame the policy and R&D agenda, especially in the context of debates such as land-sparing vs. land-sharing.