Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

You are viewing this page in draft mode.

Greenery as a mitigation and adaptation strategy to urban heat


The absence of vegetation in urban areas contributes to the establishment of the urban heat island, markedly increasing thermal stress for residents, driving morbidity and mortality. Mitigation strategies are, therefore, needed to reduce urban heat, particularly against a background of urbanization, anthropogenic warming and increasing frequency and intensity of heatwaves. In this Review, we evaluate the potential of green infrastructure as a mitigation strategy, focusing on greenery on the ground (parks) and greenery on buildings (green roofs and green walls). Green infrastructure acts to cool the urban environment through shade provision and evapotranspiration. Typically, greenery on the ground reduces peak surface temperature by 2–9 °C, while green roofs and green walls reduce surface temperature by ~17 °C, also providing added thermal insulation for the building envelope. However, the cooling potential varies markedly, depending on the scale of interest (city or building level), greenery extent (park shape and size), plant selection and plant placement. Urban planners must, therefore, optimize design to maximize mitigation benefits, for example, by interspersing parks throughout a city, allocating more trees than lawn space and using multiple strategies in areas where most cooling is required. To do so, improved translation of scientific understanding to practical design guidelines is needed.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Fig. 1: The urban heat island effect.
Fig. 2: Greenery-related cooling mechanisms in the urban environment.
Fig. 3: Average greenery-related peak temperature reductions.
Fig. 4: Factors contributing to temperature reduction for ground-level greenery.
Fig. 5: Types of greenery on buildings.
Fig. 6: Factors influencing the cooling potential of vertical and rooftop greenery.
Fig. 7: Translation of greenery research into design.


  1. 1.

    Akbari, H. & Kolokotsa, D. Three decades of urban heat islands and mitigation technologies research. Energy Build. 133, 834–842 (2016).

    Article  Google Scholar 

  2. 2.

    Oke, T. R. The energetic basis of the urban heat island. Q. J. R. Meteorol. Soc. 108, 1–24 (1982). Pioneering work describing and quantifying the urban heat island effect.

    Google Scholar 

  3. 3.

    Oke, T. R., Johnson, G. T., Steyn, D. G. & Watson, I. D. Simulation of surface urban heat islands under ‘ideal’ conditions at night part 2: Diagnosis of causation. Boundary-Layer Meteorol. 56, 339–358 (1991).

    Article  Google Scholar 

  4. 4.

    He, X. et al. Observational and modeling study of interactions between urban heat island and heatwave in Beijing. J. Clean. Prod. 247, 119169 (2020).

    Article  Google Scholar 

  5. 5.

    Santamouris, M. Analyzing the heat island magnitude and characteristics in one hundred Asian and Australian cities and regions. Sci. Total Environ. 512–513, 582–598 (2015).

    Article  Google Scholar 

  6. 6.

    Deilami, K., Kamruzzaman, M. & Liu, Y. Urban heat island effect: a systematic review of spatio-temporal factors, data, methods, and mitigation measures. Int. J. Appl. Earth Obs. Geoinf. 67, 30–42 (2018).

    Article  Google Scholar 

  7. 7.

    Rauf, S. et al. How hard they hit? Perception, adaptation and public health implications of heat waves in urban and peri-urban Pakistan. Environ. Sci. Pollut. Res. 24, 10630–10639 (2017).

    Article  Google Scholar 

  8. 8.

    Sakka, A., Santamouris, M., Livada, I., Nicol, F. & Wilson, M. On the thermal performance of low income housing during heat waves. Energy Build. 49, 69–77 (2012).

    Article  Google Scholar 

  9. 9.

    Rizvi, S. H., Alam, K. & Iqbal, M. J. Spatio-temporal variations in urban heat island and its interaction with heat wave. J. Atmos. Sol. Terr. Phys. 185, 50–57 (2019).

    Article  Google Scholar 

  10. 10.

    Founda, D. & Santamouris, M. Synergies between urban heat island and heat waves in Athens (Greece), during an extremely hot summer (2012). Sci. Rep. 7, 10973 (2017).

    Article  Google Scholar 

  11. 11.

    Heaviside, C., Vardoulakis, S. & Cai, X.-M. Attribution of mortality to the urban heat island during heatwaves in the West Midlands, UK. Environ. Health 15, S27 (2016).

    Article  Google Scholar 

  12. 12.

    Robine, J.-M. et al. Death toll exceeded 70,000 in Europe during the summer of 2003. C. R. Biol. 331, 171–178 (2008).

    Article  Google Scholar 

  13. 13.

    Le Tertre, A. et al. Impact of the 2003 heatwave on all-cause mortality in 9 French cities. Epidemiology 17, 75–79 (2006).

    Article  Google Scholar 

  14. 14.

    Tan, J. et al. The urban heat island and its impact on heat waves and human health in Shanghai. Int. J. Biometeorol. 54, 75–84 (2010).

    Article  Google Scholar 

  15. 15.

    Goggins, W. B., Chan, E. Y. Y., Ng, E., Ren, C. & Chen, L. Effect modification of the association between short-term meteorological factors and mortality by urban heat islands in Hong Kong. PLoS ONE 7, e38551 (2012).

    Article  Google Scholar 

  16. 16.

    Dang, T. N., Van, D. Q., Kusaka, H., Seposo, X. T. & Honda, Y. Green space and deaths attributable to the urban heat island effect in Ho Chi Minh City. Am. J. Public Health 108, S137–S143 (2017).

    Article  Google Scholar 

  17. 17.

    Paravantis, J., Santamouris, M., Cartalis, C., Efthymiou, C. & Kontoulis, N. Mortality associated with high ambient temperatures, heatwaves, and the urban heat island in Athens, Greece. Sustainability 9, 606 (2017).

    Article  Google Scholar 

  18. 18.

    Milojevic, A. et al. Impact of London’s urban heat island on heat-related mortality. Epidemiology 22, S182–S183 (2011).

    Article  Google Scholar 

  19. 19.

    Santamouris, M. Heat island research in Europe: the state of the art. Adv. Build. Energy Res. 1, 123–150 (2007).

    Article  Google Scholar 

  20. 20.

    Tran, H., Uchihama, D., Ochi, S. & Yasuoka, Y. Assessment with satellite data of the urban heat island effects in Asian mega cities. Int. J. Appl. Earth Obs. Geoinf. 8, 34–48 (2006).

    Article  Google Scholar 

  21. 21.

    Conry, P. et al. Chicago’s heat island and climate change: Bridging the scales via dynamical downscaling. J. Appl. Meteorol. Climatol. 54, 1430–1448 (2015).

    Article  Google Scholar 

  22. 22.

    Yang, L. et al. Contrasting impacts of urban forms on the future thermal environment: example of Beijing metropolitan area. Environ. Res. Lett. 11, 034018 (2016).

    Article  Google Scholar 

  23. 23.

    Sachindra, D. A., Ng, A. W. M., Muthukumaran, S. & Perera, B. J. C. Impact of climate change on urban heat island effect and extreme temperatures: a case-study. Q. J. R. Meteorol. Soc. 142, 172–186 (2016).

    Article  Google Scholar 

  24. 24.

    Lemonsu, A., Kounkou-Arnaud, R., Desplat, J., Salagnac, J.-L. & Masson, V. Evolution of the Parisian urban climate under a global changing climate. Clim. Change 116, 679–692 (2013).

    Article  Google Scholar 

  25. 25.

    Lauwaet, D. et al. Assessing the current and future urban heat island of Brussels. Urban Clim. 15, 1–15 (2016).

    Article  Google Scholar 

  26. 26.

    Chapman, S., Watson, J. E. M., Salazar, A., Thatcher, M. & McAlpine, C. A. The impact of urbanization and climate change on urban temperatures: a systematic review. Landsc. Ecol. 32, 1921–1935 (2017).

    Article  Google Scholar 

  27. 27.

    Li, D. et al. Contrasting responses of urban and rural surface energy budgets to heat waves explain synergies between urban heat islands and heat waves. Environ. Res. Lett. 10, 054009 (2015).

    Article  Google Scholar 

  28. 28.

    Argüeso, D., Evans, J. P., Pitman, A. J. & Di Luca, A. Effects of city expansion on heat stress under climate change conditions. PLoS ONE 10, e0117066 (2015).

    Article  Google Scholar 

  29. 29.

    Li, D. & Bou-Zeid, E. Synergistic interactions between urban heat islands and heat waves: the impact in cities is larger than the sum of its parts. J. Appl. Meteorol. Climatol. 52, 2051–2064 (2013).

    Article  Google Scholar 

  30. 30.

    Takane, Y., Ohashi, Y., Grimmond, C. S. B., Hara, M. & Kikegawa, Y. Asian megacity heat stress under future climate scenarios: impact of air-conditioning feedback. Environ. Res. Commun. 2, 015004 (2020).

    Article  Google Scholar 

  31. 31.

    Lin, C.-Y., Chien, Y.-Y., Su, C.-J., Kueh, M.-T. & Lung, S.-C. Climate variability of heat wave and projection of warming scenario in Taiwan. Clim. Change 145, 305–320 (2017).

    Article  Google Scholar 

  32. 32.

    Taha, H. Urban climates and heat islands: albedo, evapotranspiration, and anthropogenic heat. Energy Build. 25, 99–103 (1997).

    Article  Google Scholar 

  33. 33.

    Doulos, L., Santamouris, M. & Livada, I. Passive cooling of outdoor urban spaces. The role of materials. Sol. Energy 77, 231–249 (2004).

    Article  Google Scholar 

  34. 34.

    Compagnon, R. Solar and daylight availability in the urban fabric. Energy Build. 36, 321–328 (2004).

    Article  Google Scholar 

  35. 35.

    Ratti, C., Di Sabatino, S. & Britter, R. Urban texture analysis with image processing techniques: winds and dispersion. Theor. Appl. Climatol. 84, 77–90 (2006).

    Article  Google Scholar 

  36. 36.

    Sailor, D. J. A review of methods for estimating anthropogenic heat and moisture emissions in the urban environment. Int. J. Climatol. 31, 189–199 (2011).

    Article  Google Scholar 

  37. 37.

    Lin, Y. et al. Water as an urban heat sink: Blue infrastructure alleviates urban heat island effect in mega-city agglomeration. J. Clean. Prod. 262, 121411 (2020).

    Article  Google Scholar 

  38. 38.

    Bowler, D. E., Buyung-Ali, L., Knight, T. M. & Pullin, A. S. Urban greening to cool towns and cities: A systematic review of the empirical evidence. Landsc. Urban Plan. 97, 147–155 (2010). Consolidates multiple studies to quantify park cooling effects.

    Article  Google Scholar 

  39. 39.

    Besir, A. B. & Cuce, E. Green roofs and facades: A comprehensive review. Renew. Sustain. Energy Rev. 82, 915–939 (2018).

    Article  Google Scholar 

  40. 40.

    Ismail, A., Abdul Samad, M. H., Rahman, A. M. A. & Yeok, F. S. Cooling Potentials and CO2 uptake of Ipomoea Pes-caprae installed on the flat roof of a single storey residential building in Malaysia. Procedia Soc. Behav. Sci. 35, 361–368 (2012).

    Article  Google Scholar 

  41. 41.

    Nikolić, M. & Stevović, S. Family Asteraceae as a sustainable planning tool in phytoremediation and its relevance in urban areas. Urban For. Urban Green. 14, 782–789 (2015).

    Article  Google Scholar 

  42. 42.

    Lin, M.-Y. et al. The effects of vegetation barriers on near-road ultrafine particle number and carbon monoxide concentrations. Sci. Total Environ. 553, 372–379 (2016).

    Article  Google Scholar 

  43. 43.

    Cook-Patton, S. C., McArt, S. H., Parachnowitsch, A. L., Thaler, J. S. & Agrawal, A. A. A direct comparison of the consequences of plant genotypic and species diversity on communities and ecosystem function. Ecology 92, 915–923 (2011).

    Article  Google Scholar 

  44. 44.

    Menz, M. H. M. et al. Reconnecting plants and pollinators: challenges in the restoration of pollination mutualisms. Trends Plant Sci. 16, 4–12 (2011).

    Article  Google Scholar 

  45. 45.

    Takebayashi, H. & Moriyama, M. Surface heat budget on green roof and high reflection roof for mitigation of urban heat island. Build. Environ. 42, 2971–2979 (2007).

    Article  Google Scholar 

  46. 46.

    Hoyano, A. Climatological uses of plants for solar control and the effects on the thermal environment of a building. Energy Build. 11, 181–199 (1988).

    Article  Google Scholar 

  47. 47.

    Taha, H. in Analysis of Energy Efficiency of Air Quality in the South Coast Air Basin-Phase II, Report No. LBL-35728 (ed. Taha, H. et al.) 43–59 (Lawrence Berkeley National Laboratory, 1994).

  48. 48.

    Tan, P. Y. et al. A method to partition the relative effects of evaporative cooling and shading on air temperature within vegetation canopy. J. Urban Ecol. 4, juy012 (2018).

    Article  Google Scholar 

  49. 49.

    Hoelscher, M.-T., Nehls, T., Jänicke, B. & Wessolek, G. Quantifying cooling effects of facade greening: shading, transpiration and insulation. Energy Build. 114, 283–290 (2016).

    Article  Google Scholar 

  50. 50.

    Papadakis, G., Tsamis, P. & Kyritsis, S. An experimental investigation of the effect of shading with plants for solar control of buildings. Energy Build. 33, 831–836 (2001).

    Article  Google Scholar 

  51. 51.

    Simpson, J. R. Improved estimates of tree-shade effects on residential energy use. Energy Build. 34, 1067–1076 (2002).

    Article  Google Scholar 

  52. 52.

    Heisler, G. M. Energy savings with trees. J. Aboricult. 12, 113–125 (1986).

    Google Scholar 

  53. 53.

    McPherson, E. G., Herrington, L. P. & Heisler, G. M. Impacts of vegetation on residential heating and cooling. Energy Build. 12, 41–51 (1988).

    Article  Google Scholar 

  54. 54.

    McPherson, E. G., Simpson, J. R. & Livingston, M. Effects of three landscape treatments on residential energy and water use in Tucson, Arizona. Energy Build. 13, 127–138 (1989).

    Article  Google Scholar 

  55. 55.

    Parker, J. H. Landscaping to reduce the energy used in cooling buildings. J. Forestry 81, 82–105 (1983).

    Google Scholar 

  56. 56.

    Oke, T. R. Boundary Layer Climates (Routledge, 2002).

  57. 57.

    Seyam, S. The impact of greenery systems on building energy: systematic review. J. Build. Eng. 26, 100887 (2019).

    Article  Google Scholar 

  58. 58.

    He, Y., Yu, H., Ozaki, A., Dong, N. & Zheng, S. Influence of plant and soil layer on energy balance and thermal performance of green roof system. Energy 141, 1285–1299 (2017).

    Article  Google Scholar 

  59. 59.

    Cleugh, H. & Grimmond, S. in The Future of the World’s Climate 2nd edn (eds Henderson-Sellers, A. & McGuffie, K. E.) 47–76 (Elsevier, 2011).

  60. 60.

    Dabberdt, W. F. & Davis, P. A. Determination of energetic characteristics of urban-rural surfaces in the greater St. Louis area. Boundary-Layer Meteorol. 14, 105–121 (1978).

    Article  Google Scholar 

  61. 61.

    Steyn, D. & Oke, T. Effects of a small scrub fire on the surface radiation budget. Weather 35, 212–215 (1980).

    Article  Google Scholar 

  62. 62.

    Tan, C. L., Wong, N. H., Tan, P. Y., Jusuf, S. K. & Chiam, Z. Q. Impact of plant evapotranspiration rate and shrub albedo on temperature reduction in the tropical outdoor environment. Build. Environ. 94, 206–217 (2015). Quantifies plant traits for green roof shrubs and their impact on cooling.

    Article  Google Scholar 

  63. 63.

    Dobos, E. in Encyclopedia of Natural Resources-Land Vol. I (ed. Wang, Y.) 7–9 (CRC Press, 2014).

  64. 64.

    Skoulika, F., Santamouris, M., Kolokotsa, D. & Boemi, N. On the thermal characteristics and the mitigation potential of a medium size urban park in Athens, Greece. Landsc. Urban Plan. 123, 73–86 (2014).

    Article  Google Scholar 

  65. 65.

    Cheung, P. K. & Jim, C. Y. Differential cooling effects of landscape parameters in humid-subtropical urban parks. Landsc. Urban Plan. 192, 103651 (2019).

    Article  Google Scholar 

  66. 66.

    Wang, Y., Ni, Z., Peng, Y. & Xia, B. Local variation of outdoor thermal comfort in different urban green spaces in Guangzhou, a subtropical city in South China. Urban For. Urban Green. 32, 99–112 (2018).

    Article  Google Scholar 

  67. 67.

    Oliveira, S., Andrade, H. & Vaz, T. The cooling effect of green spaces as a contribution to the mitigation of urban heat: a case study in Lisbon. Build. Environ. 46, 2186–2194 (2011).

    Article  Google Scholar 

  68. 68.

    Yu, C. & Hien, W. N. Thermal benefits of city parks. Energy Build. 38, 105–120 (2006).

    Article  Google Scholar 

  69. 69.

    Zoulia, I., Santamouris, M. & Dimoudi, A. Monitoring the effect of urban green areas on the heat island in Athens. Environ. Monit. Assess. 156, 275 (2008).

    Article  Google Scholar 

  70. 70.

    Tsoka, S., Tsikaloudaki, A. & Theodosiou, T. Analyzing the ENVI-met microclimate model’s performance and assessing cool materials and urban vegetation applications–A review. Sustain. Cities Soc. 43, 55–76 (2018).

    Article  Google Scholar 

  71. 71.

    Yang, A.-S., Juan, Y.-H., Wen, C.-Y. & Chang, C.-J. Numerical simulation of cooling effect of vegetation enhancement in a subtropical urban park. Appl. Energy 192, 178–200 (2017).

    Article  Google Scholar 

  72. 72.

    Gromke, C. et al. CFD analysis of transpirational cooling by vegetation: Case study for specific meteorological conditions during a heat wave in Arnhem, Netherlands. Build. Environ. 83, 11–26 (2015).

    Article  Google Scholar 

  73. 73.

    Lin, W., Yu, T., Chang, X., Wu, W. & Zhang, Y. Calculating cooling extents of green parks using remote sensing: method and test. Landsc. Urban Plan. 134, 66–75 (2015).

    Article  Google Scholar 

  74. 74.

    Feyisa, G. L., Dons, K. & Meilby, H. Efficiency of parks in mitigating urban heat island effect: an example from Addis Ababa. Landsc. Urban Plan. 123, 87–95 (2014).

    Article  Google Scholar 

  75. 75.

    Yu, Z., Guo, X., Jørgensen, G. & Vejre, H. How can urban green spaces be planned for climate adaptation in subtropical cities? Ecol. Indic. 82, 152–162 (2017).

    Article  Google Scholar 

  76. 76.

    Cao, X., Onishi, A., Chen, J. & Imura, H. Quantifying the cool island intensity of urban parks using ASTER and IKONOS data. Landsc. Urban Plan. 96, 224–231 (2010).

    Article  Google Scholar 

  77. 77.

    Saaroni, H., Amorim, J. H., Hiemstra, J. A. & Pearlmutter, D. Urban Green Infrastructure as a tool for urban heat mitigation: Survey of research methodologies and findings across different climatic regions. Urban Clim. 24, 94–110 (2018).

    Article  Google Scholar 

  78. 78.

    Ren, Z. et al. Estimation of the relationship between urban park characteristics and park cool island intensity by remote sensing data and field measurement. Forests 4, 868–886 (2013).

    Article  Google Scholar 

  79. 79.

    Upmanis, H., Eliasson, I. & Lindqvist, S. The influence of green areas on nocturnal temperatures in a high latitude city (Göteborg, Sweden). Int. J. Climatol. 18, 681–700 (1998).

    Article  Google Scholar 

  80. 80.

    Sugawara, H. et al. Thermal influence of a large green space on a hot urban environment. J. Environ. Qual. 45, 125–133 (2016).

    Article  Google Scholar 

  81. 81.

    Nichol, J. Remote sensing of urban heat islands by day and night. Photogramm. Eng. Remote Sens. 71, 613–621 (2005).

    Article  Google Scholar 

  82. 82.

    Hamada, S. & Ohta, T. Seasonal variations in the cooling effect of urban green areas on surrounding urban areas. Urban For. Urban Green. 9, 15–24 (2010).

    Article  Google Scholar 

  83. 83.

    Wong, N. H. & Yu, C. Study of green areas and urban heat island in a tropical city. Habitat Int. 29, 547–558 (2005).

    Article  Google Scholar 

  84. 84.

    Ng, E., Chen, L., Wang, Y. & Yuan, C. A study on the cooling effects of greening in a high-density city: an experience from Hong Kong. Build. Environ. 47, 256–271 (2012).

    Article  Google Scholar 

  85. 85.

    Konarska, J., Holmer, B., Lindberg, F. & Thorsson, S. Influence of vegetation and building geometry on the spatial variations of air temperature and cooling rates in a high-latitude city. Int. J. Climatol. 36, 2379–2395 (2016).

    Article  Google Scholar 

  86. 86.

    Aflaki, A. et al. Urban heat island mitigation strategies: a state-of-the-art review on Kuala Lumpur, Singapore and Hong Kong. Cities 62, 131–145 (2017).

    Article  Google Scholar 

  87. 87.

    Shashua-Bar, L., Pearlmutter, D. & Erell, E. The cooling efficiency of urban landscape strategies in a hot dry climate. Landsc. Urban Plan. 92, 179–186 (2009).

    Article  Google Scholar 

  88. 88.

    Zhao, C., Fu, G., Liu, X. & Fu, F. Urban planning indicators, morphology and climate indicators: A case study for a north-south transect of Beijing, China. Build. Environ. 46, 1174–1183 (2011).

    Article  Google Scholar 

  89. 89.

    Honjo, T. & Takakura, T. Simulation of thermal effects of urban green areas on their surrounding areas. Energy Build. 15, 443–446 (1990).

    Article  Google Scholar 

  90. 90.

    Takebayashi, H. Influence of urban green area on air temperature of surrounding built-up area. Climate 5, 60 (2017).

    Article  Google Scholar 

  91. 91.

    Yan, H., Wu, F. & Dong, L. Influence of a large urban park on the local urban thermal environment. Sci. Total Environ. 622–623, 882–891 (2018).

    Article  Google Scholar 

  92. 92.

    Xiao, X. D., Dong, L., Yan, H., Yang, N. & Xiong, Y. The influence of the spatial characteristics of urban green space on the urban heat island effect in Suzhou Industrial Park. Sustain. Cities Soc. 40, 428–439 (2018).

    Article  Google Scholar 

  93. 93.

    Yu, Z., Guo, X., Zeng, Y., Koga, M. & Vejre, H. Variations in land surface temperature and cooling efficiency of green space in rapid urbanization: The case of Fuzhou city, China. Urban For. Urban Green. 29, 113–121 (2018).

    Article  Google Scholar 

  94. 94.

    Chang, C.-R., Li, M.-H. & Chang, S.-D. A preliminary study on the local cool-island intensity of Taipei city parks. Landsc. Urban Plan. 80, 386–395 (2007).

    Article  Google Scholar 

  95. 95.

    Jaganmohan, M., Knapp, S., Buchmann, C. M. & Schwarz, N. The bigger, the better? The influence of urban green space design on cooling effects for residential areas. J. Environ. Qual. 45, 134–145 (2016).

    Article  Google Scholar 

  96. 96.

    Lu, J., Li, C.-d., Yang, Y.-c., Zhang, X.-h. & Jin, M. Quantitative evaluation of urban park cool island factors in mountain city. J. Cent. South Univ. 19, 1657–1662 (2012).

    Article  Google Scholar 

  97. 97.

    Yu, Z. et al. Critical review on the cooling effect of urban blue-green space: a threshold-size perspective. Urban For. Urban Green. 49, 126630 (2020).

    Article  Google Scholar 

  98. 98.

    Yang, G., Yu, Z., Jørgensen, G. & Vejre, H. How can urban blue-green space be planned for climate adaption in high-latitude cities? A seasonal perspective. Sustain. Cities Soc. 53, 101932 (2020).

    Article  Google Scholar 

  99. 99.

    Yu, Z., Xu, S., Zhang, Y., Jørgensen, G. & Vejre, H. Strong contributions of local background climate to the cooling effect of urban green vegetation. Sci. Rep. 8, 6798 (2018).

    Article  Google Scholar 

  100. 100.

    Fan, H. et al. How to cool hot-humid (Asian) cities with urban trees? An optimal landscape size perspective. Agric. For. Meteorol. 265, 338–348 (2019).

    Article  Google Scholar 

  101. 101.

    Motazedian, A., Coutts, A. M. & Tapper, N. J. The microclimatic interaction of a small urban park in central Melbourne with its surrounding urban environment during heat events. Urban For. Urban Green. 52, 126688 (2020).

    Article  Google Scholar 

  102. 102.

    Du, H. et al. Quantifying the cool island effects of urban green spaces using remote sensing data. Urban For. Urban Green. 27, 24–31 (2017).

    Article  Google Scholar 

  103. 103.

    Park, J., Kim, J.-H., Lee, D. K., Park, C. Y. & Jeong, S. G. The influence of small green space type and structure at the street level on urban heat island mitigation. Urban For. Urban Green 21, 203–212 (2017).

    Article  Google Scholar 

  104. 104.

    Chen, A., Yao, X. A., Sun, R. & Chen, L. Effect of urban green patterns on surface urban cool islands and its seasonal variations. Urban For. Urban Green. 13, 646–654 (2014).

    Article  Google Scholar 

  105. 105.

    Kato, T., Yamada, T. & Hino, M. Spatial structure of air temperature and humidity in urban park forest and its surrounding. J. Inst. Sci. Eng. Chuo Univ. 12, 63–71 (2006).

    Google Scholar 

  106. 106.

    Moriyama, M., Kono, H., Yoshida, A., Miyazaki, H. & Takebayashi, H. Data analysis on ‘cool spot’ effect of green canopy in urban areas. J. Architect. Plan. Environ. Eng. 541, 49–56 (2001).

    Google Scholar 

  107. 107.

    Vaz Monteiro, M., Doick, K. J., Handley, P. & Peace, A. The impact of greenspace size on the extent of local nocturnal air temperature cooling in London. Urban For. Urban Green. 16, 160–169 (2016). Examines the cooling effect beyond park boundaries.

    Article  Google Scholar 

  108. 108.

    Sodoudi, S., Zhang, H., Chi, X., Müller, F. & Li, H. The influence of spatial configuration of green areas on microclimate and thermal comfort. Urban For. Urban Green. 34, 85–96 (2018).

    Article  Google Scholar 

  109. 109.

    Lin, T.-P., Tsai, K.-T., Hwang, R.-L. & Matzarakis, A. Quantification of the effect of thermal indices and sky view factor on park attendance. Landsc. Urban Plan. 107, 137–146 (2012).

    Article  Google Scholar 

  110. 110.

    Lee, H., Mayer, H. & Chen, L. Contribution of trees and grasslands to the mitigation of human heat stress in a residential district of Freiburg, Southwest Germany. Landsc. Urban Plan. 148, 37–50 (2016).

    Article  Google Scholar 

  111. 111.

    Rahman, M. A., Moser, A., Gold, A., Rötzer, T. & Pauleit, S. Vertical air temperature gradients under the shade of two contrasting urban tree species during different types of summer days. Sci. Total Environ. 633, 100–111 (2018).

    Article  Google Scholar 

  112. 112.

    Kotzen, B. An investigation of shade under six different tree species of the Negev desert towards their potential use for enhancing micro-climatic conditions in landscape architectural development. J. Arid Environ. 55, 231–274 (2003).

    Article  Google Scholar 

  113. 113.

    Lin, B.-S. & Lin, Y.-J. Cooling effect of shade trees with different characteristics in a subtropical urban park. HortScience 45, 83–86 (2010).

    Article  Google Scholar 

  114. 114.

    Berry, R., Livesley, S. J. & Aye, L. Tree canopy shade impacts on solar irradiance received by building walls and their surface temperature. Build. Environ. 69, 91–100 (2013).

    Article  Google Scholar 

  115. 115.

    de Abreu-Harbich, L. V., Labaki, L. C. & Matzarakis, A. Effect of tree planting design and tree species on human thermal comfort in the tropics. Landsc. Urban Plan. 138, 99–109 (2015).

    Article  Google Scholar 

  116. 116.

    Armson, D., Stringer, P. & Ennos, A. R. The effect of tree shade and grass on surface and globe temperatures in an urban area. Urban For. Urban Green. 11, 245–255 (2012).

    Article  Google Scholar 

  117. 117.

    Konarska, J., Lindberg, F., Larsson, A., Thorsson, S. & Holmer, B. Transmissivity of solar radiation through crowns of single urban trees — application for outdoor thermal comfort modelling. Theor. Appl. Climatol. 117, 363–376 (2014).

    Article  Google Scholar 

  118. 118.

    Moss, J. L., Doick, K. J., Smith, S. & Shahrestani, M. Influence of evaporative cooling by urban forests on cooling demand in cities. Urban For. Urban Green. 37, 65–73 (2019).

    Article  Google Scholar 

  119. 119.

    Tan, P. Y. et al. Transpiration and cooling potential of tropical urban trees from different native habitats. Sci. Total Environ. 705, 135764 (2020).

    Article  Google Scholar 

  120. 120.

    Thom, J. K., Coutts, A. M., Broadbent, A. M. & Tapper, N. J. The influence of increasing tree cover on mean radiant temperature across a mixed development suburb in Adelaide, Australia. Urban For. Urban Green. 20, 233–242 (2016).

    Article  Google Scholar 

  121. 121.

    Balczó, M., Gromke, C. & Ruck, B. Numerical modeling of flow and pollutant dispersion in street canyons with tree planting. Meteorol. Z. 18, 197–206 (2009).

    Article  Google Scholar 

  122. 122.

    Zhao, Q., Sailor, D. J. & Wentz, E. A. Impact of tree locations and arrangements on outdoor microclimates and human thermal comfort in an urban residential environment. Urban For. Urban Green. 32, 81–91 (2018).

    Article  Google Scholar 

  123. 123.

    Tan, P. Y., Wang, J. & Sia, A. Perspectives on five decades of the urban greening of Singapore. Cities 32, 24–32 (2013). Outlines urban greening policies for high-density urban environments.

    Article  Google Scholar 

  124. 124.

    Vijayaraghavan, K. Green roofs: A critical review on the role of components, benefits, limitations and trends. Renew. Sustain. Energy Rev. 57, 740–752 (2016).

    Article  Google Scholar 

  125. 125.

    Wong, N. H., Chen, Y., Ong, C. L. & Sia, A. Investigation of thermal benefits of rooftop garden in the tropical environment. Build. Environ. 38, 261–270 (2003).

    Article  Google Scholar 

  126. 126.

    Wong, N. H. et al. Thermal evaluation of vertical greenery systems for building walls. Build. Environ. 45, 663–672 (2010). One of the first studies to conduct measurements of green walls custom-made for experimentation.

    Article  Google Scholar 

  127. 127.

    Tan, C. L., Wong, N. H. & Jusuf, S. K. Effects of vertical greenery on mean radiant temperature in the tropical urban environment. Landsc. Urban Plan. 127, 52–64 (2014).

    Article  Google Scholar 

  128. 128.

    Bevilacqua, P., Mazzeo, D., Bruno, R. & Arcuri, N. Experimental investigation of the thermal performances of an extensive green roof in the Mediterranean area. Energy Build. 122, 63–79 (2016).

    Article  Google Scholar 

  129. 129.

    He, Y., Yu, H., Ozaki, A. & Dong, N. Thermal and energy performance of green roof and cool roof: A comparison study in Shanghai area. J. Clean. Prod. 267, 122205 (2020).

    Article  Google Scholar 

  130. 130.

    Teemusk, A. & Mander, Ü. Greenroof potential to reduce temperature fluctuations of a roof membrane: a case study from Estonia. Build. Environ. 44, 643–650 (2009).

    Article  Google Scholar 

  131. 131.

    Getter, K. L., Rowe, D. B., Andresen, J. A. & Wichman, I. S. Seasonal heat flux properties of an extensive green roof in a Midwestern US climate. Energy Build. 43, 3548–3557 (2011).

    Article  Google Scholar 

  132. 132.

    Vox, G., Blanco, I. & Schettini, E. Green façades to control wall surface temperature in buildings. Build. Environ. 129, 154–166 (2018).

    Article  Google Scholar 

  133. 133.

    Sternberg, T., Viles, H. & Cathersides, A. Evaluating the role of ivy (Hedera helix) in moderating wall surface microclimates and contributing to the bioprotection of historic buildings. Build. Environ. 46, 293–297 (2011).

    Article  Google Scholar 

  134. 134.

    Jim, C. Y. & Peng, L. L. H. Weather effect on thermal and energy performance of an extensive tropical green roof. Urban For. Urban Green. 11, 73–85 (2012).

    Article  Google Scholar 

  135. 135.

    Lee, L. S. H. & Jim, C. Y. Thermal-irradiance behaviours of subtropical intensive green roof in winter and landscape-soil design implications. Energy Build. 209, 109692 (2020).

    Article  Google Scholar 

  136. 136.

    Lee, L. S. H. & Jim, C. Y. Thermal-cooling performance of subtropical green roof with deep substrate and woodland vegetation. Ecol. Eng. 119, 8–18 (2018).

    Article  Google Scholar 

  137. 137.

    Cascone, S., Coma, J., Gagliano, A. & Pérez, G. The evapotranspiration process in green roofs: a review. Build. Environ. 147, 337–355 (2019).

    Article  Google Scholar 

  138. 138.

    Jim, C. Y. Thermal performance of climber greenwalls: effects of solar irradiance and orientation. Appl. Energy 154, 631–643 (2015).

    Article  Google Scholar 

  139. 139.

    Kotsiris, G., Nektarios, P. A., Ntoulas, N. & Kargas, G. An adaptive approach to intensive green roofs in the Mediterranean climatic region. Urban For. Urban Green. 12, 380–392 (2013).

    Article  Google Scholar 

  140. 140.

    Skinner, C. J. Urban density, meteorology and rooftops. Urban Policy Res. 24, 355–367 (2006).

    Article  Google Scholar 

  141. 141.

    Jim, C. Y. & Tsang, S. W. Biophysical properties and thermal performance of an intensive green roof. Build. Environ. 46, 1263–1274 (2011).

    Article  Google Scholar 

  142. 142.

    Yin, H., Kong, F., Dronova, I., Middel, A. & James, P. Investigation of extensive green roof outdoor spatio-temporal thermal performance during summer in a subtropical monsoon climate. Sci. Total Environ. 696, 133976 (2019).

    Article  Google Scholar 

  143. 143.

    Wong, N. H., Tan, A. Y. K., Tan, P. Y. & Wong, N. C. Energy simulation of vertical greenery systems. Energy Build. 41, 1401–1408 (2009).

    Article  Google Scholar 

  144. 144.

    Coma, J. et al. Vertical greenery systems for energy savings in buildings: a comparative study between green walls and green facades. Build. Environ. 111, 228–237 (2017).

    Article  Google Scholar 

  145. 145.

    Hohmann-Marriott, M. F. & Blankenship, R. E. Evolution of photosynthesis. Annu. Rev. Plant Biol. 62, 515–548 (2011).

    Article  Google Scholar 

  146. 146.

    Pérez, G., Coma, J., Sol, S. & Cabeza, L. F. Green facade for energy savings in buildings: the influence of leaf area index and facade orientation on the shadow effect. Appl. Energy 187, 424–437 (2017).

    Article  Google Scholar 

  147. 147.

    Saadatian, O. et al. A review of energy aspects of green roofs. Renew. Sustain. Energy Rev. 23, 155–168 (2013).

    Article  Google Scholar 

  148. 148.

    Sailor, D. J., Elley, T. B. & Gibson, M. Exploring the building energy impacts of green roof design decisions – a modeling study of buildings in four distinct climates. J. Build. Phys. 35, 372–391 (2012).

    Article  Google Scholar 

  149. 149.

    Vaz Monteiro, M. et al. Functional green roofs: importance of plant choice in maximising summertime environmental cooling and substrate insulation potential. Energy Build. 141, 56–68 (2017).

    Article  Google Scholar 

  150. 150.

    Cameron, R. W. F., Taylor, J. E. & Emmett, M. R. What’s ‘cool’ in the world of green façades? How plant choice influences the cooling properties of green walls. Build. Environ. 73, 198–207 (2014). Quantifies plant traits for green walls and their corresponding cooling effect.

    Article  Google Scholar 

  151. 151.

    Qiu, K. & Jia, B. The roles of landscape both inside the park and the surroundings in park cooling effect. Sustain. Cities Soc. 52, 101864 (2020).

    Article  Google Scholar 

  152. 152.

    Jamei, E., Rajagopalan, P., Seyedmahmoudian, M. & Jamei, Y. Review on the impact of urban geometry and pedestrian level greening on outdoor thermal comfort. Renew. Sustain. Energy Rev. 54, 1002–1017 (2016).

    Article  Google Scholar 

  153. 153.

    Giridharan, R., Lau, S. S. Y., Ganesan, S. & Givoni, B. Lowering the outdoor temperature in high-rise high-density residential developments of coastal Hong Kong: the vegetation influence. Build. Environ. 43, 1583–1595 (2008).

    Article  Google Scholar 

  154. 154.

    Langenheim, N., White, M., Tapper, N., Livesley, S. J. & Ramirez-Lovering, D. Right tree, right place, right time: a visual-functional design approach to select and place trees for optimal shade benefit to commuting pedestrians. Sustain. Cities Soc. 52, 101816 (2020).

    Article  Google Scholar 

  155. 155.

    Nordh, H. & Østby, K. Pocket parks for people – a study of park design and use. Urban For. Urban Green. 12, 12–17 (2013).

    Article  Google Scholar 

  156. 156.

    Lin, P., Lau, S. S. Y., Qin, H. & Gou, Z. Effects of urban planning indicators on urban heat island: a case study of pocket parks in high-rise high-density environment. Landsc. Urban Plan. 168, 48–60 (2017).

    Article  Google Scholar 

  157. 157.

    Mayor of London. The London plan. Spatial development strategy for Greater London. Greater London Authority (2019).

  158. 158.

    Urban Redevelopment Authority. Singapore master plan. URA (2019).

  159. 159.

    Ong, B. L. Green plot ratio: an ecological measure for architecture and urban planning. Landsc. Urban Plan. 63, 197–211 (2003).

    Article  Google Scholar 

  160. 160.

    Espinal, R. L. Jr et al. A local law to amend the administrative code of the city of New York and the New York city building code, in relation to requiring that the roofs of certain buildings be covered in green roofs or solar photovoltaic electricity generating systems. The New York City Council (2019).

  161. 161.

    United Nations Framework Convention on Climate Change. France mandates green roofs. UNFCCC (2015).

  162. 162.

    Legislative Council Secretariat. Environmental issues in Tokyo (LegCo, 2006).

  163. 163.

    US Green Building Council. LEED public policies. USGBC (2010).

  164. 164.

    Hong Kong Green Building Council (HKGBC). BEAM Plus new buildings version 2.0. HKGBC (2019).

  165. 165.

    Building Construction Authority. Green mark for non-residential buildings (GM NRB: 2015) (BCA, 2016).

  166. 166.

    Norton, B. A. et al. Planning for cooler cities: a framework to prioritise green infrastructure to mitigate high temperatures in urban landscapes. Landsc. Urban Plan. 134, 127–138 (2015).

    Article  Google Scholar 

  167. 167.

    Santamouris, M., Cartalis, C., Synnefa, A. & Kolokotsa, D. On the impact of urban heat island and global warming on the power demand and electricity consumption of buildings — a review. Energy Build. 98, 119–124 (2015).

    Article  Google Scholar 

  168. 168.

    Jim, C. Y. Assessing growth performance and deficiency of climber species on tropical greenwalls. Landsc. Urban Plan. 137, 107–121 (2015).

    Article  Google Scholar 

  169. 169.

    Chen, X. et al. Canopy transpiration and its cooling effect of three urban tree species in a subtropical city- Guangzhou, China. Urban For. Urban Green. 43, 126368 (2019).

    Article  Google Scholar 

  170. 170.

    von Arx, G., Graf Pannatier, E., Thimonier, A. & Rebetez, M. Microclimate in forests with varying leaf area index and soil moisture: potential implications for seedling establishment in a changing climate. J. Ecol. 101, 1201–1213 (2013).

    Article  Google Scholar 

  171. 171.

    Peri, G., Rizzo, G., Scaccianoce, G., La Gennusa, M. & Jones, P. Vegetation and soil – related parameters for computing solar radiation exchanges within green roofs: are the available values adequate for an easy modeling of their thermal behavior? Energy Build. 129, 535–548 (2016).

    Article  Google Scholar 

  172. 172.

    Rahman, M. A. et al. Traits of trees for cooling urban heat islands: a meta-analysis. Build. Environ. 170, 106606 (2020). A meta-analysis examining tree functional traits for improved cooling potential.

    Article  Google Scholar 

  173. 173.

    Santamouris, M. et al. Progress in urban greenery mitigation science–assessment methodologies advanced technologies and impact on cities. J. Civ. Eng. Manag. 24, 638–671 (2018). A comprehensive review of urban greenery research trends.

    Article  Google Scholar 

  174. 174.

    American Society of Heating, Refrigerating and Air-Conditioning Engineers. Standard 55 – Thermal environmental conditions for human occupancy (ASHRAE, 2010).

  175. 175.

    Bröde, P. et al. Deriving the operational procedure for the universal thermal climate index (UTCI). Int. J. Biometeorol. 56, 481–494 (2012).

    Article  Google Scholar 

  176. 176.

    Rahman, M. A. et al. Tree cooling effects and human thermal comfort under contrasting species and sites. Agric. For. Meteorol. 287, 107947 (2020).

    Article  Google Scholar 

  177. 177.

    Hami, A., Abdi, B., Zarehaghi, D. & Maulan, S. B. Assessing the thermal comfort effects of green spaces: A systematic review of methods, parameters, and plants’ attributes. Sustain. Cities Soc. 49, 101634 (2019).

    Article  Google Scholar 

  178. 178.

    Moradpour, M., Afshin, H. & Farhanieh, B. A numerical investigation of reactive air pollutant dispersion in urban street canyons with tree planting. Atmos. Pollut. Res. 8, 253–266 (2017).

    Article  Google Scholar 

  179. 179.

    Hsieh, C.-M., Jan, F.-C. & Zhang, L. A simplified assessment of how tree allocation, wind environment, and shading affect human comfort. Urban For. Urban Green. 18, 126–137 (2016).

    Article  Google Scholar 

  180. 180.

    Buccolieri, R., Santiago, J.-L., Rivas, E. & Sáanchez, B. Reprint of: Review on urban tree modelling in CFD simulations: Aerodynamic, deposition and thermal effects. Urban For. Urban Green. 37, 56–64 (2019).

    Article  Google Scholar 

  181. 181.

    Morakinyo, T. E., Ouyang, W., Lau, K. K.-L., Ren, C. & Ng, E. Right tree, right place (urban canyon): tree species selection approach for optimum urban heat mitigation — development and evaluation. Sci. Total Environ. 719, 137461 (2020). Examines tree selection and placement for shade optimization.

    Article  Google Scholar 

  182. 182.

    Jim, C. Y. & Chen, W. Y. Assessing the ecosystem service of air pollutant removal by urban trees in Guangzhou (China). J. Environ. Manag. 88, 665–676 (2008).

    Article  Google Scholar 

  183. 183.

    Shwartz, A., Turbé, A., Simon, L. & Julliard, R. Enhancing urban biodiversity and its influence on city-dwellers: an experiment. Biol. Conserv. 171, 82–90 (2014).

    Article  Google Scholar 

  184. 184.

    Twohig-Bennett, C. & Jones, A. The health benefits of the great outdoors: a systematic review and meta-analysis of greenspace exposure and health outcomes. Environ. Res. 166, 628–637 (2018).

    Article  Google Scholar 

  185. 185.

    Han, Y., Taylor, J. E. & Pisello, A. L. Toward mitigating urban heat island effects: Investigating the thermal-energy impact of bio-inspired retro-reflective building envelopes in dense urban settings. Energy Build. 102, 380–389 (2015).

    Article  Google Scholar 

  186. 186.

    Aram, F., Higueras García, E., Solgi, E. & Mansournia, S. Urban green space cooling effect in cities. Heliyon 5, e01339 (2019).

    Article  Google Scholar 

  187. 187.

    Wang, Y. & Akbari, H. The effects of street tree planting on urban heat island mitigation in Montreal. Sustain. Cities Soc. 27, 122–128 (2016).

    Article  Google Scholar 

Download references

Author information




C.L.T. led the research, discussion, writing and editing of the article. N.H.W., D.D.K. and H.T. contributed to the writing.

Corresponding author

Correspondence to Chun Liang Tan.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Peer review information

Nature Reviews Earth & Environment thanks Amirhosein Ghaffarianhoseini, Tijana Blanusa, Mohammad Asrafur Rahman, Paul Osmond and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

Publisher’s note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information


Sensible heat

Heat transfer that results in a change in temperature between objects, without changing the volume or pressure.


The combined processes of evaporation of water from the soil, as well as plant transpiration, where water is transported from the soil through the roots and exits via the leaf stomata and into the atmosphere as water vapour.

UHI intensity

The temperature difference between urban and rural areas; either surface or air temperature can be used.


The ratio of reflected radiation over total incident radiation on a surface, indicating its overall reflecting potential. Albedo values can range from 0 to 1, with 1 meaning all radiation is reflected and 0 indicating that all radiation is being absorbed.

Latent heat

Heat transfer that results in a change in state (such as liquid into vapour), without changing the temperature.

Bowen ratio

The ratio of sensible heat flux to latent heat flux above a surface that contains moisture. Commonly used in meteorological and hydrological studies, it is an indication of the abundance of water over surfaces, as the presence of moisture will directly influence latent heat flux density.

Threshold value of efficiency

(TVoE). The value to which an increase in green space ceases to provide substantial cooling.

Leaf area index

(LAI). Total one-sided leaf area per unit horizontal ground surface.

Vapour pressure deficit

The difference between moisture content in in situ air compared with the total moisture the air can hold when it is saturated.

Physiological equivalent temperature

Air temperature at which, in a typical indoor setting, the heat balance of the human body is maintained with core and skin temperatures equal to those under the conditions being assessed. It provides an indication of thermal comfort, applicable for both indoors and outdoors.

Computational fluid dynamics

(CFD). Quantitative modelling of fluid flow based on the laws of mass, momentum and energy conservation that govern fluid motion.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Wong, N.H., Tan, C.L., Kolokotsa, D.D. et al. Greenery as a mitigation and adaptation strategy to urban heat. Nat Rev Earth Environ 2, 166–181 (2021).

Download citation


Quick links