A Review of the Water–Carbon Nexus in Urban Systems

The rapid development of cities has brought a lot carbon emissions and water consumption, leading to disasters, such as the greenhouse effect drought. However, there is lack systematic review on key nodes for water–carbon nexus points water-saving emission reduction improvement in urban systems. This study reviewed definition nexus, analyzed its changing mechanism different systems, concluded major methodologies applied studies. main findings are follows: (1) water/wastewater treatment systems structure transformation energy nexus. (2) From perspective methodologies, research focus gradually changed from single system process analysis multi-system whole analysis. (3) There tendency sacrifice large consumption exchange calling explorations balance. (4) More comprehensive methods, data support, accurate boundaries required quantify systematically existing achievements providing support metabolism related policy makings.