Unpacking the compactness-emission nexus with the moderating role of environmental governance: Evidence from urban built-up areas in eastern China

Compact development and low-carbon development in urban areas are critical pathways to tackle the problems concerning urban sprawl and climate change, which are pivotal for fostering and achieving urban sustainability. However, whether pursuing urban compactness constrains the realization of low-carbon goals remains to be elucidated. Accordingly, this study investigates the compactness-emission nexus and possible strategies for synchronizing compact urban development with carbon reduction. Using a city-level panel dataset covering 84 cities in eastern China over nine observed years in 2012–2022, the study first measures urban compactness through land use intensity, population density and land use mix; carbon emissions are measured by per unit built-up area carbon emission (UCE) and per capita carbon emissions (PCE). Then, the study employs panel regression models to analyze their relationships and the moderating role of environmental governance. Conclusions are majorly threefold. Firstly, the degree of urban compactness in eastern Chinese cities has increased over the past decade. Secondly, different dimensions of urban compactness have varying impacts on carbon emissions. Population density exhibits a significant negative effect on both UCE and PCE, while the growing land use intensity significantly elevates carbon emissions. Thirdly, environmental governance plays a significant moderating role in strengthening the impact of population density on carbon emission mitigation. With high governance intensity, the marginal effect of population density on UCE reverses from + 0.37 to –1.25, while its negative effect on PCE is further reinforced from –0.46 to –12.83. These findings offer policy-relevant insights for high-density cities in eastern China and, more broadly, for developing cities to confront the climate-urbanization challenge and sustainability transition pressures.