The Nonlinear Relationship Between Urbanization and Ecological Environment in China Under the PSR (Pressure-State-Response) Model: Inflection Point Identification and Policy Pathways

In the process of social development, there is a contradiction between economic development and the ecological environment. Western countries were the first to experience the inverted U-shaped development model of “destruction first and compensation later”, and China is also facing similar problems. To reveal the formation mechanism and dynamic evolution of the inflection point of ecological environment changes in China, this paper combines the entropy weight method, the analytic hierarchy process, and quadratic curve fitting to construct the “Ecological Pressure Index—GDPP Model” and studies the inflection point of ecological pressure during China’s economic development from 2000 to 2022. The study shows that the key inflection point of China’s ecological environment pressure is between 2016 and 2017, which is mainly affected by multiple factors such as the economy, domestic and international situations, and policy adjustments. For example, the implementation of the “Supply-side Structural Reform” and the environmental protection supervision system has significantly reduced the pollution pressure. At the same time, the “inflection point” is applied to dynamically adjust the PSR model, revealing the stage transition of China’s environmental governance focus. For instance, from 2000 to 2016, end-of-pipe pollution treatment was dominant (for example, the weights of pollution emission indicators X5–X8 were relatively high), while after 2016, the focus of governance shifted to the restoration of ecological space (for example, the weight of nature reserves X22 was 2.759%). The theoretical contribution of this paper lies in proposing the concept of “Policy-driven EKC”, emphasizing the core role of policy intervention in the formation of the inflection point of the ecological environment. In addition, the dynamic adjustment of the PSR model using the “inflection point” better interprets China’s self-transformation in the development process and provides other developing countries with a Chinese solution of “institutional innovation first” and the “Policy-driven EKC—Chinese PSR Model” for reference in balancing economic growth and ecological protection.