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Trees halve urban heat island effect globally but unequal benefits only modestly mitigate climate-change warming

Published Article

Global

Publication date: May 6, 2026

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This global analysis shows urban tree cover reduces heat island effects and cools cities, benefiting millions of people. However, cooling varies widely and only modestly offsets future climate warming, highlighting the need for equitable tree planting in vulnerable urban areas.

Subject Tags

  • Forest
  • Climate adaptation
  • Climate impacts

Abstract

Although tree cover reduces the urban heat island, no global estimate quantifies air temperature reductions by contemporary or future tree cover, currently and with climate change. Here, we estimate these reductions for all 8,919 large urban areas. Current urban tree cover mitigates 41–49% of the maximum potential air-temperature urban heat island that would occur in the absence of tree canopy. Tree canopy reduces summer air temperature by a population-weighted mean of 0.15 ± 0.03 °C, with wide variation (0.0–2.7 °C), benefiting 914 (805–1040, 95% CI) million people by >0.25 °C. Cooling benefits are greater in already cooler areas: high-income countries and suburbs. Current and plausible future tree cover mitigate only ~10% (6.7–18% and 6.3–17%, respectively) of the median mid-century climate-change warming under a moderate emission scenario. Our results suggest tree canopy expansion in densely settled low-income urban areas is necessary for equitable urban heat island mitigation and climate adaptation.

Citation

McDonald, R. I., Chakraborty, T. C., Endreny, T. A., Parsons, L. A., Marsagishvili, M., & Esperon-Rodriguez, M. (2026). Trees halve urban heat island effect globally but unequal benefits only modestly mitigate climate-change warming. Nature communications, 17(1), 3569.

TNC Authors

  • Robert I. McDonald (Rob)
    Lead Scientist for Nature-based Solutions. Europe
    The Nature Conservancy
    Email: rob_mcdonald@tnc.org

  • Luke A. Parsons
    Applied Climate Modeling Scientist. Global Science
    The Nature Conservancy
    Email: luke.parsons@tnc.org

  • Mariami Marsagishvili
    The Nature Conservancy