County green transformation: how does gross ecosystem product assessment promote common prosperity?

Gross ecosystem product (GEP) refers to the direct measurement of a region's ecosystem product supply capabilities and the basis for value realisation. China has made clear arrangements for establishing GEP assessment regulations, with 36 districts and counties currently conducting GEP assessment, of which 24 districts and counties have executed dual assessments of regional gross domestic product (GDP) and GEP. To explore the influence of GEP assessment on the common prosperity of urban and rural regions, this study conducts a quasi-natural experiment using the staggered difference-in-differences model to examine data from 1946 districts and counties from 2012 to 2022. The results reveal that GEP assessment can significantly reduce the urban-rural income gap and improve rural residents' income, thereby realising common prosperity. Further analysis indicates that GEP assessment promotes faster income growth for rural residents and a narrowing of the income gap between urban and rural residents through enhanced government attention, fiscal support, green finance, and agricultural development. The impact of GEP assessment on common prosperity is obviously heterogeneous. The ability of GEP assessment to promote common prosperity is stronger in key ecological function areas, districts and counties with strong fiscal capacity and high public environmental concern. This study confirms the positive role of GEP assessment in increasing rural residents' income and advancing common prosperity. The results also provide a decision-making reference for the expedient implementation of GEP assessment.