Impact of lifestyle, human diet, and nutrient use efficiency in food production on eutrophication of global aquifers and surface waters

This analysis starts from the middle-of-the-road (SSP2) and the sustainability (SSP1) Shared Socioeconomic Pathways (SSP), focusing on the year 2050. The scenarios with changed lifestyle assume a reduction of food wastage and a low-meat diet for all world inhabitants, implying large reductions of meat and milk consumption and production in industrialised countries. Scenarios with improved nutrient use efficiencies assume maximum achievable efficiencies under practical conditions. The SSP2 scenario combined with assumptions on lifestyle and human diet leads to improvement in industrialised countries only, and increased levels in many other regions. A strong improvement is achieved in SSP1, but not in many developing countries, and SSP1 combined with changed lifestyle leads to improvement of groundwater and surface water quality in industrialised countries only. Therefore, changed lifestyle needs to be combined with efforts to improve the efficiency in food production systems and wastewater treatment to achieve reductions of the area affected by groundwater contamination and eutrophication of surface waters. Reduction strategies need to find a balance between N and P, since it is easier to reduce N in rivers to levels below the threshold than P.