A new approach to investigation of human influences on the environment identifies social organization as an influence independent of population size, affluence, and technology. The framework also identifies population events, such as births, that influence the environment. The authors use longitudinal, multilevel, mixed-method measures of local land use changes, population dynamics, and social organization to test this framework. These tests reveal that changes in social organization are strongly associated with changes in land use independent of measures of population size, affluence, and technology. Also, local birth events shape local land use changes and key proximate determinants of land use change.