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.
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Akbari, H. & Kolokotsa, D. Three decades of urban heat islands and mitigation technologies research. Energy Build. 133, 834–842 (2016).
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.
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).
He, X. et al. Observational and modeling study of interactions between urban heat island and heatwave in Beijing. J. Clean. Prod. 247, 119169 (2020).
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).
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).
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).
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).
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).
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).
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).
Robine, J.-M. et al. Death toll exceeded 70,000 in Europe during the summer of 2003. C. R. Biol. 331, 171–178 (2008).
Le Tertre, A. et al. Impact of the 2003 heatwave on all-cause mortality in 9 French cities. Epidemiology 17, 75–79 (2006).
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).
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).
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).
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).
Milojevic, A. et al. Impact of London’s urban heat island on heat-related mortality. Epidemiology 22, S182–S183 (2011).
Santamouris, M. Heat island research in Europe: the state of the art. Adv. Build. Energy Res. 1, 123–150 (2007).
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).
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).
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).
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).
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).
Lauwaet, D. et al. Assessing the current and future urban heat island of Brussels. Urban Clim. 15, 1–15 (2016).
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).
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).
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).
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).
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).
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).
Taha, H. Urban climates and heat islands: albedo, evapotranspiration, and anthropogenic heat. Energy Build. 25, 99–103 (1997).
Doulos, L., Santamouris, M. & Livada, I. Passive cooling of outdoor urban spaces. The role of materials. Sol. Energy 77, 231–249 (2004).
Compagnon, R. Solar and daylight availability in the urban fabric. Energy Build. 36, 321–328 (2004).
Ratti, C., Di Sabatino, S. & Britter, R. Urban texture analysis with image processing techniques: winds and dispersion. Theor. Appl. Climatol. 84, 77–90 (2006).
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).
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).
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.
Besir, A. B. & Cuce, E. Green roofs and facades: A comprehensive review. Renew. Sustain. Energy Rev. 82, 915–939 (2018).
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).
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).
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).
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).
Menz, M. H. M. et al. Reconnecting plants and pollinators: challenges in the restoration of pollination mutualisms. Trends Plant Sci. 16, 4–12 (2011).
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).
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).
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).
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).
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).
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).
Simpson, J. R. Improved estimates of tree-shade effects on residential energy use. Energy Build. 34, 1067–1076 (2002).
Heisler, G. M. Energy savings with trees. J. Aboricult. 12, 113–125 (1986).
McPherson, E. G., Herrington, L. P. & Heisler, G. M. Impacts of vegetation on residential heating and cooling. Energy Build. 12, 41–51 (1988).
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).
Parker, J. H. Landscaping to reduce the energy used in cooling buildings. J. Forestry 81, 82–105 (1983).
Oke, T. R. Boundary Layer Climates (Routledge, 2002).
Seyam, S. The impact of greenery systems on building energy: systematic review. J. Build. Eng. 26, 100887 (2019).
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).
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).
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).
Steyn, D. & Oke, T. Effects of a small scrub fire on the surface radiation budget. Weather 35, 212–215 (1980).
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.
Dobos, E. in Encyclopedia of Natural Resources-Land Vol. I (ed. Wang, Y.) 7–9 (CRC Press, 2014).
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).
Cheung, P. K. & Jim, C. Y. Differential cooling effects of landscape parameters in humid-subtropical urban parks. Landsc. Urban Plan. 192, 103651 (2019).
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).
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).
Yu, C. & Hien, W. N. Thermal benefits of city parks. Energy Build. 38, 105–120 (2006).
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).
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).
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).
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).
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).
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).
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).
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).
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).
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).
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).
Sugawara, H. et al. Thermal influence of a large green space on a hot urban environment. J. Environ. Qual. 45, 125–133 (2016).
Nichol, J. Remote sensing of urban heat islands by day and night. Photogramm. Eng. Remote Sens. 71, 613–621 (2005).
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).
Wong, N. H. & Yu, C. Study of green areas and urban heat island in a tropical city. Habitat Int. 29, 547–558 (2005).
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).
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).
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).
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).
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).
Honjo, T. & Takakura, T. Simulation of thermal effects of urban green areas on their surrounding areas. Energy Build. 15, 443–446 (1990).
Takebayashi, H. Influence of urban green area on air temperature of surrounding built-up area. Climate 5, 60 (2017).
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).
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).
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).
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).
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).
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).
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).
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).
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).
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).
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).
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).
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).
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).
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).
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).
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.
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).
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).
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).
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).
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).
Lin, B.-S. & Lin, Y.-J. Cooling effect of shade trees with different characteristics in a subtropical urban park. HortScience 45, 83–86 (2010).
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).
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).
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).
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).
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).
Tan, P. Y. et al. Transpiration and cooling potential of tropical urban trees from different native habitats. Sci. Total Environ. 705, 135764 (2020).
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).
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).
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).
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.
Vijayaraghavan, K. Green roofs: A critical review on the role of components, benefits, limitations and trends. Renew. Sustain. Energy Rev. 57, 740–752 (2016).
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).
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.
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).
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).
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).
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).
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).
Vox, G., Blanco, I. & Schettini, E. Green façades to control wall surface temperature in buildings. Build. Environ. 129, 154–166 (2018).
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).
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).
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).
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).
Cascone, S., Coma, J., Gagliano, A. & Pérez, G. The evapotranspiration process in green roofs: a review. Build. Environ. 147, 337–355 (2019).
Jim, C. Y. Thermal performance of climber greenwalls: effects of solar irradiance and orientation. Appl. Energy 154, 631–643 (2015).
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).
Skinner, C. J. Urban density, meteorology and rooftops. Urban Policy Res. 24, 355–367 (2006).
Jim, C. Y. & Tsang, S. W. Biophysical properties and thermal performance of an intensive green roof. Build. Environ. 46, 1263–1274 (2011).
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).
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).
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).
Hohmann-Marriott, M. F. & Blankenship, R. E. Evolution of photosynthesis. Annu. Rev. Plant Biol. 62, 515–548 (2011).
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).
Saadatian, O. et al. A review of energy aspects of green roofs. Renew. Sustain. Energy Rev. 23, 155–168 (2013).
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).
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).
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.
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).
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).
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).
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).
Nordh, H. & Østby, K. Pocket parks for people – a study of park design and use. Urban For. Urban Green. 12, 12–17 (2013).
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).
Mayor of London. The London plan. Spatial development strategy for Greater London. Greater London Authority https://www.london.gov.uk/what-we-do/planning/london-plan/new-london-plan/intend-publish-london-plan-2019 (2019).
Urban Redevelopment Authority. Singapore master plan. URA https://www.ura.gov.sg/Corporate/Planning/Master-Plan (2019).
Ong, B. L. Green plot ratio: an ecological measure for architecture and urban planning. Landsc. Urban Plan. 63, 197–211 (2003).
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 https://legistar.council.nyc.gov/LegislationDetail.aspx?ID=3557657&GUID=B4C3A822-2FBB-45FD-8A74-C59DD95246C1&Options=ID%7cText%7c&Search=1032 (2019).
United Nations Framework Convention on Climate Change. France mandates green roofs. UNFCCC https://unfccc.int/news/france-mandates-green-roofs (2015).
Legislative Council Secretariat. Environmental issues in Tokyo (LegCo, 2006).
US Green Building Council. LEED public policies. USGBC https://s3.amazonaws.com/legacy.usgbc.org/usgbc/docs/Archive/General/Docs691.pdf (2010).
Hong Kong Green Building Council (HKGBC). BEAM Plus new buildings version 2.0. HKGBC https://www.hkgbc.org.hk/eng/beam-plus/file/BEAMPlus_New_Buildings_v2_0.pdf (2019).
Building Construction Authority. Green mark for non-residential buildings (GM NRB: 2015) (BCA, 2016).
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).
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).
Jim, C. Y. Assessing growth performance and deficiency of climber species on tropical greenwalls. Landsc. Urban Plan. 137, 107–121 (2015).
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).
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).
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).
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.
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.
American Society of Heating, Refrigerating and Air-Conditioning Engineers. Standard 55 – Thermal environmental conditions for human occupancy (ASHRAE, 2010).
Bröde, P. et al. Deriving the operational procedure for the universal thermal climate index (UTCI). Int. J. Biometeorol. 56, 481–494 (2012).
Rahman, M. A. et al. Tree cooling effects and human thermal comfort under contrasting species and sites. Agric. For. Meteorol. 287, 107947 (2020).
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).
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).
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).
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).
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.
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).
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).
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).
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).
Aram, F., Higueras García, E., Solgi, E. & Mansournia, S. Urban green space cooling effect in cities. Heliyon 5, e01339 (2019).
Wang, Y. & Akbari, H. The effects of street tree planting on urban heat island mitigation in Montreal. Sustain. Cities Soc. 27, 122–128 (2016).
The authors declare no competing interests.
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- 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.
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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). https://doi.org/10.1038/s43017-020-00129-5
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