Jiang et al. (2025) Nonlinear impacts of urban size and vegetation cover on global surface urban heat: Insights from 6022 cities

Identification

• Journal: Remote Sensing of Environment
• Year: 2025
• Date: 2025-11-28
• Authors: Song Jiang, Yongling Zhao, Lei Zhao, Dominik Strebel, Dominique Derome, Diana Ürge-Vorsatz, Jan Carmeliet, Jian Peng
• DOI: 10.1016/j.rse.2025.115154

Research Groups

• Laboratory for Earth Surface Processes, Ministry of Education, College of Urban and Environmental Sciences, Peking University, Beijing, China
• Department of Mechanical and Process Engineering, ETH Zürich, Zürich, Switzerland
• Department of Civil and Environmental Engineering, University of Illinois Urbana-Champaign, Urbana, IL, USA
• Institute for Sustainability, Energy, and Environment (iSEE), University of Illinois at Urbana-Champaign, Urbana, IL, USA
• National Center for Supercomputing Applications, University of Illinois Urbana-Champaign, Urbana, IL, USA
• Department of Civil and Building Engineering, Université de Sherbrooke, Sherbrooke, QC, Canada
• Department of Environmental Sciences and Policy, Central European University, Vienna, Austria

Short Summary

This study globally assesses surface urban heat island (SUHI) across 6022 cities to reveal nonlinear impacts of urban size and vegetation cover, finding distinct SUHI intensification patterns and compounded thermal stress in Global South cities.

Objective

• To present a globally consistent assessment of 6022 cities to understand the nonlinear effects of urban size and vegetation cover on surface urban heat islands (SUHI) across climate zones.

Study Configuration

• Spatial Scale: Global, covering 6022 cities.
• Temporal Scale: Summer of 2019 for primary analysis, validated with multi-year records (2017–2021).

Methodology and Data

• Models used: A self-developed, scalable SUHI quantification method enabling cross-climate comparisons.
• Data sources: MODIS Aqua data (MYD11A2).

Main Results

• SUHI intensification exhibits distinct rapid- and slow-growth zones with urban size, with the fastest increase occurring in small cities (below the top 20% of global urban size).
• This uneven rise in SUHI intensity is attributed to synergistic effects of urban expansion and vegetation loss.
• Vegetation cooling shows saturation beyond an inflection point, with the equatorial zone demonstrating weaker cooling efficiency and earlier saturation onset.
• Global South cities experience 3.37 ± 0.14 °C higher absolute temperatures and 0.24 ± 0.05 °C greater SUHI intensity compared to cities in the Global North.

Contributions

• Provides a globally consistent and cross-climate comparable assessment of SUHI for 6022 cities using a novel quantification method.
• Reveals nonlinear impacts of urban size and vegetation cover on SUHI, identifying critical thresholds and differentiated responses across climate zones.
• Highlights compounded thermal stress in Global South cities through a dual-perspective framework integrating absolute and relative temperature metrics.
• Establishes a planning-relevant framework to guide targeted and climate-sensitive urban heat mitigation strategies.

Funding

• Not mentioned in the provided text.

Citation

@article{Jiang2025Nonlinear,
  author = {Jiang, Song and Zhao, Yongling and Zhao, Lei and Strebel, Dominik and Derome, Dominique and Ürge-Vorsatz, Diana and Carmeliet, Jan and Peng, Jian},
  title = {Nonlinear impacts of urban size and vegetation cover on global surface urban heat: Insights from 6022 cities},
  journal = {Remote Sensing of Environment},
  year = {2025},
  doi = {10.1016/j.rse.2025.115154},
  url = {https://doi.org/10.1016/j.rse.2025.115154}
}