Simulating and estimating tempo-spatial patterns in global human appropriation of net primary production (HANPP): A consumption-based approach

Anthropogenic alterations of biomass flows in earthʹs biogeochemical cycles may profoundly affect the amount of biomass available, the level of biodiversity and the extent of carbon sequestration in global terrestrial ecosystems. Quantitative assessments of humanityʹs impacts on ecosystem structures and services are therefore essential for projections of changes in terrestrial vegetation. Human appropriation of photosynthetic production (HANPP) has been extensively used as an ecological indicator for monitoring direct human interventions into terrestrial ecosystems. Here, we present the results of tempo-spatial estimations of the loss of net primary production by global terrestrial ecosystems due to human consumption-based appropriation (cHANPP, an aggregate ecological indicator for evaluating human impacts on terrestrial ecosystems due to harvesting and processing of plants for consumption) from 2000 to 2050. Our estimates are based on previously derived estimate of global biomass harvest and use for the year 2000 (Krausmann et al., 2008) through association with IPAT (Impact = Population × Affluence × Technology) model used for estimating the influence of changes in population, per capita consumption demands and technology employed during harvesting and processing of plants on biomass consumption. Our results show a distinct tendency toward increased global cHANPP by 0.17 Pg C yr−1 (P < 0.001) from 2000 to 2050 (changes resulting from land conversion are excluded), mainly resulting from an increased global population size and intensified per capita consumption of agricultural products. Long-term trends and spatial patterns in cHANPP exhibit significant variations across countries and geographical zones owing to tempo-spatial variations of both population size and consumption patterns. The proportion of potentially available photosynthetic production appropriated by human consumption, estimated at approximately ∼28% in the 2000s, is projected to increase to approximately ∼33% in the 2040s. Our results also indicate that technology may play a crucial role for alleviating the growing impact of human activities on terrestrial ecosystems and provide potential insights for sustainable development in the context of management issues and decision making.