Emergy Synthesis and Regional Sustainability Assessment: Case Study of Pan-Pearl River Delta in China

In this paper, emergy analysis is used in association with the ternary diagrams and geographic information system (GIS) tools to improve the evaluation of sustainability for the Pan-Pearl River Delta (PPRD) region. Emergy accounting of PPRD is estimated, and various emergy-based indicators are reported. Ternary diagrams are drawn to provide a graphical representation of the emergy accounting data. Finally, the GIS tools are employed to assist in the emergy-based spatial analysis, and emergy density based on flat land area is mapped to reflect the intensity of emergy use in human activity areas. Results show the following: (1) the current development path of the PPRD region, with the value of emergy sustainability index (ESI = 0.227) significantly lower than one, is unsustainable in the long run; (2) Guangdong has the lowest ESI value (0.071), and the ESI values of Fujian, Guangxi, Hunan and Jiangxi are lower than 0.5, indicating that the economy in these provinces overly relies on non-renewable and imported resources; (3) Guizhou has a high emergy yield rate and is thus the main energy supplier in PPRD; and (4) among the nine provinces in PPRD, only Hainan has an ESI value (2.145) higher than one