Objective This study advances a theoretical framework for examining the impact of urbanization on local carbon emissions over space and time. It conceptualizes urbanization at the local level as a set of three distinct but related subprocesses of population concentration, land‐use intensification, and systemic interaction, which join together to exert countervailing effects on local carbon emissions. Methods To test this framework we conduct cross‐sectional and panel regression analyses of carbon emissions at the county level across the continental United States, controlling for spatial autocorrelation. Results Findings strongly support our framework and show how different dimensions of urbanization push against one another at the local level to influence carbon emissions in ways that exert far more consistent effects than household density and alternative transit use. Conclusion These findings illuminate the complexities of urbanization as a local force of environmental transformation with increasingly global consequences.