Multi-Temporal Analysis of Environmental Carrying Capacity and Coastline Changes in Yueqing City

With the rapid development of coastal cities, environmental problems are becoming increasingly severe. Therefore, it is imminent to assess the environmental carrying capacity (ECC) of coastal cities. We take Yueqing City, China, as the study area and establish an ECC evaluation system. For the objectivity and scientificity of this study, the coefficient of variation-back propagation neural network (CV-BPNN) method is used to determine the weight of the indicators and a multi-temporal evaluation is conducted. This paper also explores the relationship between coastline changes and ECC variations for the first time. The results indicate: (1) The ECC of Yueqing City first decreased and then increased, and the inland ECC is better than the coastal area. The future trend is expected to rise. (2) The coastline is continuously extending seaward, and the natural coastline retention rate gradually declines. (3) The coupling coordination degree between the change in the ECC and the change in the coastline shows a trend of “first fluctuation, then stability, and then decline,” and the ecological environment situation was still challenging. (4) Based on the above results, some suggestions are put forward to strengthen coastal ecological development and promote the sustainable development of coastal cities.