Minimizing the ecological footprint of food: closing yield and efficiency gaps simultaneously?

摘要

Agriculture as a source of food has a substantial spillover that affects the Earth's ecosystems. This results in an 'ecological footprint' of food: negative environmental impacts per capita. The footprint depends on the dietary choice of types and amounts of food, on the non-consumed part of product flows and its fate ('waste' or 'reused'), on transport and processing along the value chain, on the environmental impacts of production per unit area, and on the area needed per unit product. Yield gaps indicate inefficiency in this last aspect: resource-use efficiency gaps for water and nutrients indicate that environmental impacts per unit area are higher than desirable. Ecological intensification aimed at simultaneously closing these two gaps requires process-level understanding and system-level quantification of current efficiency of the use of land and other production factors at multiple scales (field, farm, landscape, regional and global economy). Contrary to common opinion, yield and efficiency gaps are partially independent in the empirical evidence. Synergy in gap closure is possible in many contexts where efforts are made but are not automatic. With Good Agricultural Practice (GAP), enforceable in world trade to control hidden subsidies, there is scope for incremental improvement towards food systems that are efficient at global, yet sustainable at local, scales.