China's urban green growth from 2000 to 2020 is influenced by legacy effects

With rapid urbanization, urban green spaces (UGS) are critical to maintaining urban ecosystems and the health and well-being of residents. Improving UGS is included in UN Sustainable Development Goal 11.7 (SDG 11.7), which aims to achieve universal access to safe, inclusive, and accessible green and public spaces by 2030, especially for women and children, the elderly, and people with disabilities. However, the growth rate of urban green space (GRUGS) is affected by factors such as urban built-up (UBA) area expansion, population growth, and air pollution. Therefore, in this study, 291 cities in China are divided into 15 urban agglomerations (UA), and the factors affecting the growth rate of urban green spaces (GRUGS) in China over 20 years are explored using 2000 to 2020 Chinese Urban built-up area, population, and PM 2.5 data. The results show that (1) the fastest growing area of green space in urban clusters in China is Greater Bay Area (2) Urban built-up area (UBA) is found to be the main factor influencing the GRUGS in urban agglomerations in China, i.e., the heritage effect is the main reason for the growth of urban green space in China. This study is of great significance and reference value for improving the green development of Chinese urban agglomerations by analyzing the factors that have influenced the growth of GRUGS in Chinese urban agglomerations over the past 20 years.