Scaling law reveals unbalanced urban development in China

Managing complex cities for sustainability requires coordinated development of different urban functions. Urban scaling theory provides a quantitative framework to explore the temporal change of urban properties against city size and reveal if urbanization is balanced or not. We modeled urban allometries for Chinese cities from 1984 to 2019 and quantified the variation in the scaling exponents for assessing the degree of unbalanced development across urban functions. We found urban China had weaker scaling relationships than its developed counterparts. The exponents for most urban functions showed different trajectories from those of developed countries and did not converge to the theoretical exponents. The temporally divergent exponents showed a strong unbalanced development, particularly between socio-economic and social service functions. Our study indicates that although unbalanced development could stimulate urban growth, excessive imbalance ultimately limits urban development of Chinese cities. The best urban development is achieved at an intermediate functional imbalance.