Network analysis of virtual water in the global fossil fuel trade from 2000-2016

This study uses network analysis to describe several rapid and profound shifts in the global fossil fuel trade from 2000 to 2016, and attempts to delineate changes in the corresponding embodied, or virtual, water associated with this trade (estimated here to be roughly 97 billion m^3 in aggregate in 2000 and 111 billion m^3 in 2016). This effort highlights not only the recent rise in unconventional oil and gas extraction, but also the correspondingly rapid reorganization of global geopolitical alliances around the continuing extraction of fossil energy from newly accessible reserves. Building on previous work, we draw a clear conceptual distinction between water inputs to energy systems and the impacts on water and land resources from energy systems. This distinction is particularly salient to nexus considerations surrounding the possible global expansion of shale oil and gas development. In addition to the amount of water this could require in the future (estimated to be between 1.5 and 21 billion m^3/yr in a recent study), it is also important to assess the risk to the future viability of global water resources and ecosystems resulting from these activities. Existing and new methods to assess current and potential multi-scalar impacts are explored.