Abstract:Phosphorus (P) is one of three nutrients (together with nitrogen and potassium) essential for plant growth. It is also an important non-renewable, non-metal mineral resource. With economic development and population increases, phosphorus scarcity has become an important global challenge to the sustainability of agriculture, the economy, and the environment. To analyze human influences on phosphorus flow, research has simulated anthropogenic-centered phosphorus flows within socioeconomic systems and sub-systems. This paper reviewed recent progress in phosphorus flow analysis, identified the characteristics and insufficiencies of existing studies, and projected future avenues of development for phosphorus flow analysis. Existing studies may be categorized according to the scale of the socioeconomic system (or sub-system) into four levels-global, national (including multi-national), regional, or city level-as well as either enterprise or product level. Presently, most studies have been conducted at the global or national (or multi-national) levels, while few has been performed at regional or city levels, or at enterprise or product levels. So far, more than 15 countries and multi-national regions have carried out phosphorus flow analyses, most of which focused on disturbances due to agriculture and food production and consumption. A few studies have examined disturbances due to forestry, iron and steel production, and energy sector activities, and the potential for increasing phosphorus use efficiencies in these sectors. In addition, most current studies use static models, and few employ dynamic models that consider long-term changes in phosphorus stocks. Fewer studies combines classical methods and tools, such as life-cycle analysis or input-output analysis, with material flow analysis or substance flow analysis (MFA or SFA). We identified five topics for future researches:(1) dynamic simulations of phosphorus flow with consideration of long-term changes in important driving forces (population, diet, bio-energy development, etc.) and in phosphorus stocks, (2) phosphorus footprint analyses at various scales or for various sectors of economic development, (3) the critical need for phosphorus for social and economic development, compared to that of other elements (such as metals or rare earth elements), (4) the vulnerability of phosphorus to global changes (particularly climate change), and (5) the relationship between phosphorus and other important elements (such as carbon, nitrogen, or metal elements). To meet future research demands, it is necessary to develop a dynamic model of phosphorus flow and to combine traditional material flow analyses with current tools and models, both from industrial ecology and from other disciplines. These may include economic models, input-output analyses, life-cycle analyses, network analyses, and computable general equilibrium models, and agent-based models, all required to project the effects of global changes, socio-economic development, and technological innovation on phosphorus flow and the resulting environmental impacts.