The authors constructed a social capital composite index and tested different specifications of impacts on CO2 emissions of social capital and income and functional forms, linear and non-linear. The system generalized method of moments is used to account for endogeneity in the presence of dynamic and spatial effects.

Results show significant negative and positive effects of social capital and income on emissions, respectively. The authors conclude that enhanced trust and civic engagement could complement other public policy mechanisms in driving down CO2 emissions.