Dynamic decomposition and regional differences of urban emergy ecological footprint in the Yangtze River Delta

Maintaining the balance between the economy and the environment and further realizing sustainable economic development has become an important topic. The existing research has not used the emergy ecological footprint model to calculate the ecological footprint of the Yangtze River Delta, nor have they used the factor decomposition method to analyze the influencing factors affecting the ecological footprint change. The differences in the emergy ecological footprint among different provinces and cities have not been studied. This study reported the emergy ecological footprint in the Yangtze River Delta region from 2008 to 2020. The Logarithmic Mean Divisia Index model (LMDI) was constructed to decompose the change of emergy ecological footprint into the land structure, technology, economy, and population factors to screen the main influencing factors. Gini coefficient and Theil index were used to further analyze the main influencing factors which caused the differences in the footprints at regional and intra-regional levels. The results show that: (1) The fluctuation of the per capita emergy ecological footprint in the Yangtze River Delta region has decreased, while the fluctuation of the per capita emergy ecological carrying capacity has increased. However, the per capita emergy ecological deficit is still high, where the sustainable development of the regional economy is not optimistic. (2) Technology and economy are the main factors affecting the emergy ecological footprint of the Yangtze River Delta. (3) Regional differences refer to the differences between different provinces, while intra-regional differences refer to the difference between cities within the province. In the Yangtze River Delta region, the intra-regional differences are the main reasons causing the technical differences, while the regional differences are the main reasons causing the economic differences. The significance of the study is that scientific analysis of the sustainable development status and utilization degree of resources and environment are vital for realizing the sustainable development of the Yangtze River Delta region. By decomposing the factors affecting sustainable development, the regional differences of these factors could be analyzed and serve as a theoretical basis for local governments to formulate policies to minimise the emergy ecological footprint of a targeted region.