Spatio-temporal evolution and multi-subject influencing factors of urban green development efficiency in China: Under the carbon neutral vision constraint

• Introduced the carbon–neutral ideas to construct the C-GDE assessment framework. • The SBM-Undesirable model was used to measure the C-GED’s of 284 cities in China. • Explored the effect of multi-subject factors on C-GDE using panel Tobit model. • Average level of urban C-GDE showed a “V” shaped trend of “decreasing-increasing”. A crucial strategic choice for China’s sustainable growth in the new era is the carbon peak & carbon neutral (30–60) aim, which has set new and higher requirements for the green and sustainable development of cities in the new era, and the carbon peak & carbon neutral level is gradually becoming one of the important indicators of the green and sustainable development of cities. Based on disentangling the connotation of urban green development under the vision of carbon neutrality, this study constructed a framework system for assessing urban green development in the new era, measured and portrayed the spatial and temporal variation characteristics of green development efficiency (C-GDE) under the carbon neutrality constraint in 284 prefecture-level and above cities in China using the SBM-Undesirable model, and further explored the effect of multi-subject factors on urban C-GDE using the panel Tobit model. The main findings are as follows. (1) The average allocation level of C-GDE in Chinese cities has remained at a low level from 2009 to 2019, with an overall “V”-shaped trend of “down → up”, increasing from 0.4031 to 0.5206, an overall increase of 29.15 %. (2) The overall C-GDE of Chinese cities showed the decreasing characteristics of “western cities > eastern cities > central cities”, “super cities > small cities > medium cities > large cities > mega cities > mega cities”, “non class cluster cities > class II cities > class III cities > class I cities”, and “agriculture-led cities > industry-led cities > balanced development cities > business and tourism service cities”. (3) The spatio-temporal pattern of urban C-GDE was influenced by multiple factors such as individual-level factors, enterprise-level factors, government-level factors, and other basic-level characteristic factors. Each factor, through its own evolution or coupling with other factors, continuously shaped the internal development of the urban system and promotes the greening process and urban C-GDE. Finally, targeted recommendations were made based on the findings of the study.