Lee et al. (2026) Global patterns of urban heat shaped by climate and morphology

Identification

• Journal: Nature Communications
• Year: 2026
• Date: 2026-05-11
• Authors: Siwoo Lee, Cheolhee Yoo, Bokyung Son, Dongjin Cho, Jungho Im, T. C. Chakraborty
• DOI: 10.1038/s41467-026-73062-8

Research Groups

• Department of Civil, Urban, Earth, and Environmental Engineering, Ulsan National Institute of Science and Technology (UNIST), South Korea
• Smart City Convergence Major and Department of Urban Planning and Engineering, Pusan National University, South Korea
• Environmental Planning Institute, Seoul National University, South Korea
• Pacific Northwest National Laboratory (PNNL), USA

Short Summary

The study quantifies the joint influence of urban morphology and background climate on the urban heat island (UHI) effect across 2,213 cities globally, revealing that while denser structures universally increase heat, the climatic drivers vary by region.

Objective

• To quantify the thermal influence of surrounding urban structure (morphology) and its coupling with background climate on global urban heat and to project future changes.

Study Configuration

• Spatial Scale: Global (covering 2,213 cities).
• Temporal Scale: Long-term climatology and future projections.

Methodology and Data

• Models used: Machine learning and a six-class urban typology.
• Data sources: Long-term climatology data and urban morphology datasets.

Main Results

• Thermal Impact Metric: Defined the city-level thermal impact of the surrounding built environment ($T_{BE}$) as the area-weighted UHI change induced by specific built-up types.
• Climatic Influence: Cold regions most frequently exhibit high daytime $T{BE}$, whereas arid regions dominate high nighttime $T{BE}$.
• Morphological Influence: A universal pattern was identified where denser and taller urban forms correspond to high $T{BE}$, while sparser and lower types correspond to low $T{BE}$ for both day and night.
• Future Projections: Climate change is the dominant driver of $T_{BE}$ change in 69% of the analyzed cities.
• Regional Divergence: The Global South exhibits a stronger tendency toward morphology-driven and synergistic heat intensification compared to the Global North.

Contributions

• The research provides a global-scale quantification of how urban form and climate interact to shape urban heat, shifting the focus from general UHI observations to the specific coupling of morphology and climate to inform locally tailored adaptation strategies.

Funding

• National Research Foundation of Korea (NRF) Grant through the Ministry of Science and Information and Communication Technology (MSIT) (nos. NRF-2021R1A2C2008561 and RS-2025-02310080).
• U.S. Department of Energy (DOE) Office of Science’s Biological and Environmental Research program (DOE Early Career Award).

Citation

@article{Lee2026Global,
  author = {Lee, Siwoo and Yoo, Cheolhee and Son, Bokyung and Cho, Dongjin and Im, Jungho and Chakraborty, T. C.},
  title = {Global patterns of urban heat shaped by climate and morphology},
  journal = {Nature Communications},
  year = {2026},
  doi = {10.1038/s41467-026-73062-8},
  url = {https://doi.org/10.1038/s41467-026-73062-8}
}