Human Appropriation of Net Primary Production: Patterns, Trends, and Planetary Boundaries.
Economic and population growth result in increasing use of biophysical resources, including land and biomass. Human activities influence the biological productivity of land, altering material and energy flows in the biosphere. The human appropriation of net primary production (HANPP) is an integrated socioecological indicator quantifying effects of human-induced changes in productivity and harvest on ecological biomass flows. We discuss how HANPP is defined, measured, and interpreted. Two principal approaches for constructing HANPP assessments exist: (a) In an area-specific approach, HANPP serves as an indicator of land-use intensity, gauging impacts on terrestrial ecosystems in a defined area; and (b) the consumption-based 'embodied HANPP' approach allows assessment of impacts related to individual products or the aggregate consumption of nation-states. The HANPP framework can help to estimate upper limits for the biosphere's capacity to provide humanity with biomass for food, fiber, and bioenergy and to analyze systemic feedbacks between the delivery of these resources. We outline HANPP's global patterns and trajectories and how HANPP relates to planetary boundaries, global resource use, and pressures on biodiversity.