The Temperature Paradox of Urban Form: Decoding the Evolutionary Logic Driven by Global Urban Cooling Demand

As a core unit for global climate change adaptation and mitigation, the physical form of cities has become a key variable determining their thermodynamic fate. With the intensification of global warming, the annual average indoor cooling demand (Urban Cooling Demand, UCD) within cities is expected to continue to climb. However, in the macro-process of urbanization, we observe a structural paradox: not all cities heat up in sync with increases in population and economic scale; different urban forms follow distinct growth paths, leading to entirely different cooling demand response patterns.

This study focuses on three core processes of urban volume growth—lateral expansion, structural development (such as vertical densification), and infilling. The interaction of these processes jointly shapes the spatial distribution of the urban heat island effect and ultimately determines the degree of reliance of cities on cooling energy.

Structural Break from Scale to Form

Volume growth driven by urbanization is heterogeneous. Traditional linear growth models struggle to explain why, under similar macro-population increases, the cooling pressures of different urban clusters diverge sharply. Research indicates that cities adopting broad, irregular patterns of lateral expansion exhibit relatively the fastest UCD growth rates, even if their initial demand is lower. This suggests that under low-density, peripheral urbanization contexts, the cumulative effect of heat load is exponential.