Evolution of multiple global virtual material flows.

The world is connected through multiple flows of material, but a comprehensive assessment of their temporal dynamics and interactions is rare. To address this knowledge gap, we assessed the evolution and interactions of global flows of virtual water, energy, land, CO2, nitrogen as well as financial capital embodied in international trade from 1995 to 2008. We found that the volumes of all these flows, except for land flow, increased over time. Financial capital flows increased most (188.9%), followed by flows of CO2 (59.3%), energy (58.1%), water (50.7%) and nitrogen (10.5%), while land transfer decreased by 8.8%. Volumes of virtual material flows among distant countries were much higher than those among adjacent countries. The top five countries accounted for a surprisingly large proportion (47% to 80%) of total flow volumes. Different kinds of virtual material flows tended to enhance each other through synergistic effects, and CO2 and nitrogen flows tended to have stronger positive synergetic impacts on the other virtual material flows. Our results suggest that it is important to pay particular attention to such fast-growing material flows, promote cooperation between distant countries, and target countries with the largest flows to achieve global sustainable development goals.