Social trust contributes to the reduction of urban carbon dioxide emissions

The need for the reduction of carbon dioxide (CO2) emissions has become a global consensus because of the huge effects on the global environment. Exploring the influencing factors of CO2 emissions is fundamental to reducing CO2. We explore the effect of social trust on urban CO2 emissions using the hierarchical linear model using data from China. The effect of social trust, as a type of informal rule, on urban CO2 emissions is significant, and the increase in the social trust will mitigate the annual increase in CO2 emissions. These findings highlight the importance of social trust in CO2 emissions. When studying environmental issues, the influence of informal rules needs to be considered as much as possible to control environmental problems better and achieve sustainable development goals.