China's housing boom creates systematic oversupply across all provinces with major carbon costs

Housing oversupply has emerged as a critical challenge in China's rapid urbanization, yet its systematic patterns and environmental consequences remain poorly understood. Here we analyze housing supply-demand imbalances across 28 Chinese provinces from 2010 to 2020 and present the following findings: (1) housing construction systematically exceeded population growth in all provinces without exception, with oversupply magnitudes ranging from 5% in Sichuan to 42.6% in Jilin, (2) counterfactual decomposition reveals that housing expansion effects and population migration effects operate through independent causal pathways, with housing effects dominating in northern provinces while migration effects compound problems in northeastern regions, and (3) carbon emissions from housing oversupply contribute approximately 0.24 tonnes CO2 equivalent per capita per decade, with material emissions from excess construction accounting for 72.6% of total housing-related carbon growth. These findings demonstrate that institutional distortions in China's land finance system generate persistent supply-demand decoupling that undermines both housing market efficiency and climate objectives, providing crucial insights for coordinated urban development and environmental policy reforms.