When Efficiency Becomes Fragility: The Vertical Urbanization Paradox in Chinese Cities

As global urbanization accelerates, the scarcity of land and the rising burden of housing affordability have become pressing challenges for cities worldwide. To house growing populations within limited space, many governments have turned to vertical expansion as a strategy to increase land-use efficiency. Yet, the same policies that drive high-rise construction can also embed long-term vulnerabilities. This study introduces the concept of the Vertical Urbanization Paradox, namely the idea that land-supply restrictions designed to enhance spatial efficiency may inadvertently generate economic, social, and safety fragilities over time. Using a multi-source dataset covering 276 Chinese cities from 2007 to 2022, including over one million residential projects, 700,000 housing transactions, and detailed land-transfer records, we quantify how policy-induced land-supply contraction drives building height and shapes long-term housing depreciation. Results show that slower growth in residential land supply is associated with taller buildings, with this pattern more pronounced in cities experiencing rapid GDP growth and strong population pressure. However, taller buildings experience faster depreciation and higher fire-safety risks, reflecting systemic governance and maintenance challenges. By linking short-term efficiency to long-term fragility, the study reveals how China’s vertical expansion offers both a model and a warning for rapidly urbanizing regions worldwide. Achieving sustainable vertical growth requires not only optimizing land efficiency but also strengthening institutional capacity, maintenance systems, and social equity to ensure resilient urban futures.