Evaluation of ecosystem sustainability in Changchun City, China based on improved emergy analysis and fuzzy clustering integration model

The urban composite ecosystem was broken down into three daughter systems of nature, economics, and society to prevent the uncertainty of results arising from the disagreement of assessment indices. In addition, the traditional method for emergy analysis was improved and integrated with the fuzzy clustering model in order to provide a new method for the proper evaluation of the health of urban ecosystems from the perspective of energy-material coupling. With this new method, the health of urban ecosystem in Changchun, China was evaluated. Results showed that by continuously adjusting the energy structure, the industry structure, and the development mode, the urban ecosystem of Changchun City gradually transitioned from the unhealthy to the healthy status. However, a membership value of only 0.77 indicated the weak health of the ecosystem where the environmental load rate gradually increased every year. Emergy analysis using the fuzzy clustering integration model demonstrated the whole health status of urban composite systems with a certain degree of operability and replicability.