Abstract
High air temperatures are a public health threat, causing 1300 deaths annually in the United States (US) along with heat-related morbidity and increased electricity consumption for air-conditioning (AC). Increasing tree canopy cover has been proposed as one way to reduce urban air temperatures. Here, we assemble tree cover and developed land-cover information for 97 US cities, housing 59 million people, and use regression relationships to analyze how much current urban tree cover reduces summer (JJA) air temperatures and associated heat-related mortality, morbidity, and electricity consumption. We find that 78% of urban dwellers are in neighborhoods with less than 20% tree cover. Some 15.0 million people (25% of total) experience a reduction of 0.5–1.0°C from tree cover, with another 7.9 million (13% of total) experiencing a reduction of greater than 1.0°C. Current relationships between temperature and health outcomes imply that urban tree cover helps avoid 245–346 deaths annually. Heat–mortality relationships in the 1980s, when a smaller fraction of US households had AC, imply a greater role in the past for urban tree cover in avoiding heat-related mortality. As AC availability has increased, the value of tree cover for avoiding heat-related mortality has decreased, while the value of tree cover for reducing electricity consumption likely has increased. Currently, for the 97 cities studied, the total annual economic value of avoided mortality, morbidity, and electricity consumption is an estimated $1.3–2.9 billion, or $21–49 annually per capita. Applying our results to the entire US urban population, we estimate urban tree cover annually supplies heat-reduction services worth $5.3–12.1 billion.
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References
Akbari H. 2002. Shade trees reduce building energy use and CO2 emissions from power plants. Environmental Pollution 116:S119–26.
Association American Public Works. 2007. Urban forestry best management practices for public works managers: budgeting and funding. Washington, DC: American Public Works Association.
Anderson GB, Bell ML. 2011. Heat waves in the United States: mortality risk during heat waves and effect modification by heat wave characteristics in 43 US communities. Environmental Health Perspectives 119:210.
Barreca A, Clay K, Deschenes O, Greenstone M, Shapiro JS. 2016. Adapting to climate change: the remarkable decline in the US temperature-mortality relationship over the twentieth century. Journal of Political Economy 124:105–59.
Berko J, Ingram DD, Saha S, Parker JD. 2014. Deaths attributed to heat, cold, and other weather events in the United States, 2006-2010. National Health Statistics Report 76:1–15.
Bobb JF, Peng RD, Bell ML, Dominici F. 2014. Heat-related mortality and adaptation to heat in the United States. Environmental Health Perspectives 122:811.
Boeckmann M, Rohn I. 2014. Is planned adaptation to heat reducing heat-related mortality and illness? A systematic review. BMC Public Health 14:1112.
Coutts AM, Harris RJ, Phan T, Livesley SJ, Williams NS, Tapper NJ. 2016. Thermal infrared remote sensing of urban heat: hotspots, vegetation, and an assessment of techniques for use in urban planning. Remote Sensing of Environment 186:637–51.
Davis RE, Hondula DM, Patel AP. 2016. Temperature observation time and type influence estimates of heat-related mortality in seven US cities. Environmental Health Perspectives 124:795.
Davis RE, Knappenberger PC, Michaels PJ, Novicoff WM. 2003. Changing heat-related mortality in the United States. Environmental Health Perspectives 111:1712.
Declet-Barreto J, Knowlton K, Jenerette GD, Buyantuev A. 2016. Effects of urban vegetation on mitigating exposure of vulnerable populations to excessive heat in Cleveland, Ohio. Weather, Climate, and Society 8:507–24.
EIA. 2015. Residential Energy Consumption Survey. Washington, DC. Available online at https://www.eia.gov/consumption/residential/data/2015/#ac.: US Energy Information Administration. Accessed December 2017.
EIA. 2016. Electric Sales, Revenue, and Average Price. Washington, DC. Online at https://www.eia.gov/electricity/sales_revenue_price/. US Energy Information Administration. Accessed December 2017.
Endreny T, Santagata R, Perna A, De Stefano C, Rallo R, Ulgiati S. 2017. Implementing and managing urban forests: A much needed conservation strategy to increase ecosystem services and urban wellbeing. Ecological Modelling 360:328–35.
EPA. 2014. Reducing Urban Heat Islands: Compendium of Strategies (draft). Washington, DC: Environmental Protection Agency.
Gasparrini A, Guo Y, Hashizume M, Kinney PL, Petkova EP, Lavigne E, Zanobetti A, Schwartz JD, Tobias A, Leone M. 2015. Temporal variation in heat–mortality associations: a multicountry study. Environmental Health Perspectives 123:1200.
Gasparrini A, Guo Y, Hashizume M, Lavigne E, Tobias A, Zanobetti A, Schwartz JD, Leone M, Michelozzi P, Kan H. 2016. Changes in susceptibility to heat during the summer: a multicountry analysis. American Journal of Epidemiology 183:1027–36.
Gronlund CJ, Zanobetti A, Schwartz JD, Wellenius GA, O’Neill MS. 2014. Heat, heat waves, and hospital admissions among the elderly in the United States, 1992–2006. Environmental Health Perspectives 122:1187.
Guo Y, Gasparrini A, Armstrong B, Li S, Tawatsupa B, Tobias A, Lavigne E, Coelho MdSZS, Leone M, Pan X. 2014. Global variation in the effects of ambient temperature on mortality: a systematic evaluation. Epidemiology (Cambridge, Mass.) 25:781.
Hales S, Kovats S, Lloyd S, Campbell-Lendrum D. 2014. Quantitiative risk assessment of the effects of climate change on selected causes of death, 2030 s and 2050s. Geneva: World Health Organization.
Homer C, Dewitz J, Yang L, Jin S, Danielson P, Xian G, Coulston J, Herold N, Wickham J, Megown K. 2015. Completion of the 2011 National Land Cover Database for the conterminous United States–representing a decade of land cover change information. Photogrammetric Engineering & Remote Sensing 81:345–54.
Hondula DM, Balling RC, Vanos JK, Georgescu M. 2015. Rising temperatures, human health, and the role of adaptation. Current Climate Change Reports 1:144–54.
IMF. 2017. World economic outlook database. Washington, DC: International Monetary Fund.
Imhoff ML, Zhang P, Wolfe RE, Bounoua L. 2010. Remote sensing of the urban heat island effect across biomes in the continental USA. Remote Sensing of Environment 114:504–13.
Jenerette GD, Harlan SL, Buyantuev A, Stefanov WL, Declet-Barreto J, Ruddell BL, Myint SW, Kaplan S, Li X. 2016. Micro-scale urban surface temperatures are related to land-cover features and residential heat related health impacts in Phoenix, AZ USA. Landscape Ecology 31:745–60.
Kalkstein LS, Greene S, Mills DM, Samenow J. 2011. An evaluation of the progress in reducing heat-related human mortality in major US cities. Natural Hazards 56:113–29.
Keeler BL, Hamel P, McPhearson T, Hamann MH, Donahue ML, Prado KAM, Arkema KK, Bratman GN, Brauman KA, Finlay JC. 2019. Social-ecological and technological factors moderate the value of urban nature. Nature Sustainability 2:29.
Kingsley SL, Eliot MN, Gold J, Vanderslice RR, Wellenius GA. 2016. Current and projected heat-related morbidity and mortality in Rhode Island. Environmental Health Perspectives 124:460.
Kniesner TJ, Viscusi WK, Woock C, Ziliak JP. 2012. The value of a statistical life: evidence from panel data. Review of Economics and Statistics 94:74–87.
Knowlton K, Rotkin-Ellman M, Geballe L, Max W, Solomon GM. 2011. Six climate change–related events in the United States accounted for about $14 billion in lost lives and health costs. Health Affairs 30:2167–76.
Kochanek K, Murphy S, Xu J, Tejada-Vera B. 2016. Deaths: final data for 2014. National Vital Statistics Report. 65.
Kroeger T, McDonald RI, Boucher T, Zhang P, Wang L. 2018. Where the people are: Current trends and future potential targeted investments in urban trees for PM10 and temperature mitigation in 27 U.S. cities. Landscape and Urban Planning 177:227–40.
Matthies F, Bickler G, Marin N, Hales S. 2008. Heat-health action plans. Copenhagen: WHO Regional Office for Europe.
McDonald RI. 2015. Conservation for cities: How to plan & build natural infrastructure. Washington, DC: Island Press.
McDonald RI, Aljabar L, Aubuchon C, Birnbaum H, Chandler C, Toomey W, Daley J, Jimenez W, Trieschman E, Paque J, Zeiper M. 2017. Funding trees for health: An analysis of finance and policy actions to enable tree planting for public health. Washington, DC: The Nature Conservancy.
McDonald RI, Kroeger T, Boucher T, Wang L, Salem R. 2016. Planting healthy air: a global analysis of the role of urban trees in addressing particulate matter pollution and extreme heat. Arlington, VA: The Nature Conservancy.
McFarland J, Zhou Y, Clarke L, Sullivan P, Colman J, Jaglom WS, Colley M, Patel P, Eom J, Kim SH. 2015. Impacts of rising air temperatures and emissions mitigation on electricity demand and supply in the United States: a multi-model comparison. Climatic Change 131:111–25.
McMichael A, Campbell-Lendrum D, Kovats S, Edwards S, Wilkinson P, Wilson T, Nicholls R, Hales S, Tanser F, Le Sueur D, Schlesinger M, Andronova N. 2004. Global Climate Change. In: Ezzati M, Lopez AD, Rodgers A, Murray C, Eds. Comparative quantification of health risks: global and regional burden of disease attributable to selected major risk factors. Geneva: World Health Organization.
McPherson EG, van Doorn N, de Goede J. 2015. The State of California’s Street Trees. Davis, CA: Pacific Southwest Research Station, U.S. Forest Service.
McPherson G, Simpson JR, Peper PJ, Maco SE, Xiao QF. 2005. Municipal forest benefits and costs in five US cities. Journal of Forestry 103:411–16.
Middel A, Chhetri N, Quay R. 2015. Urban forestry and cool roofs: assessment of heat mitigation strategies in Phoenix residential neighborhoods. Urban Forestry & Urban Greening 14:178–86.
Murphy KM, Topel RH. 2006. The value of health and longevity. Journal of Political Economy 114:871–904.
NOAA. 2017. Global Historical Climatology Network. Administration NOaA editor. Online at: https://www.ncdc.noaa.gov/data-access/land-based-station-data/land-based-datasets/global-historical-climatology-network-ghcn. Accessed October 2017.
Nordio F, Zanobetti A, Colicino E, Kloog I, Schwartz J. 2015. Changing patterns of the temperature–mortality association by time and location in the US, and implications for climate change. Environment International 81:80–6.
Nowak DJ, Appleton N, Ellis A, Greenfield E. 2017. Residential building energy conservation and avoided power plant emissions by urban and community trees in the United States. Urban Forestry & Urban Greening 21:158–65.
Nowak DJ, Greenfield EJ. 2018. Declining urban and community tree cover in the United States. Urban Forestry & Urban Greening 32:32–55.
OECD/IEA. 2018. The future of cooling: opportunities for energy-efficient air conditioning. https://webstore.iea.org/the-future-of-cooling: International Energy Agency (IEA).
Oke TR. 1982. The energetic basis of the urban Heat Island. Quarterly Journal of the Royal Meteorological Society 108:1–24.
Radeloff VC. 2010. 2010 Wildland urban interface (WUI) dataset. http://silvis.forest.wisc.edu/maps/wui/2010/download. Accessed October 2017.
Radeloff VC, Hammer RB, Stewart S, Fried J, Holcomb S, McKeefry J. 2005. The wildland-urban interface in the United States. Ecological Applications 15:799–805.
Robine J, Cheung S, Le Roy S, Van Oyen H, Griffiths C, Michel J, Herrmann F. 2008. Death toll exceeded 70,000 in Europe during the summer of 2003. Comptes Rendus Biologies 331:171–8.
Roy S, Byrne J, Pickering C. 2012. A systematic quantitative review of urban tree benefits, costs, and assessment methods across cities in different climatic zones. Urban Forestry & Urban Greening 11:351–63.
Santamouris M, Cartalis C, Synnefa A, Kolokotsa D. 2015. On the impact of urban heat island and global warming on the power demand and electricity consumption of buildings: a review. Energy and Buildings 98:119–24.
Schmeltz MT, Petkova EP, Gamble JL. 2016. Economic burden of hospitalizations for heat-related illnesses in the United States, 2001–2010. International Journal of Environmental Research and Public Health 13:894.
Son J-Y, Gouveia N, Bravo MA, de Freitas CU, Bell ML. 2016. The impact of temperature on mortality in a subtropical city: effects of cold, heat, and heat waves in São Paulo, Brazil. International Journal of Biometeorology 60:113–21.
Stone B Jr, Vargo J, Liu P, Habeeb D, DeLucia A, Trail M, Hu Y, Russell A. 2014. Avoided heat-related mortality through climate adaptation strategies in three US cities. PLoS ONE 9:e100852.
Taylor J. 1996. An introduction to error analysis: the study of uncertainties in physical measurements. Herndon, VA, USA: University Science Books.
Vogt J, Hauer RJ, Fischer BC. 2015. The costs of maintaining and not maintaining the urban forest: a review of the urban forestry and arboriculture literature. Arboriculture & Urban Forestry 41:293–323.
Wouters H, De Ridder K, Demuzere M, Lauwaet D, van Lipzig NPM. 2013. The diurnal evolution of the urban heat island of Paris: a model-based case study during Summer 2006. Atmospheric Chemistry & Physics 13:8525–41.
Wu J, Zhou Y, Gao Y, Fu JS, Johnson BA, Huang C, Kim Y-M, Liu Y. 2014. Estimation and uncertainty analysis of impacts of future heat waves on mortality in the eastern United States. Environmental Health Perspectives 122:10.
Zhang P, Bounoua L, Imhoff M, Wolfe R, Thome K. 2014. Comparison of MODIS land surface temperature and air temperature over the continental USA meteorological stations. Canadian Journal of Remote Sensing 40:110–22.
Acknowledgements
The authors thank their institutions for research support during the writing of this paper. RIM and TK were supported by a grant from the China Global Conservation Fund. PH thanks the Marianne and Marcus Wallenberg Foundation for their financial support. We also thank those who created the datasets used in this paper, including the NLCD, WUI, and the Global Historical Climatology Network. Without their data, our analysis would not have been possible.
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The group jointly designed the research. RIM coordinated data analysis and wrote the paper with the help of the other coauthors. PZ assembled the information on air temperature and land cover, while PH worked on the methodology for estimating heat-related impacts. TK led the economic valuation analysis.
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Figure S1
The strength of the statistical relationship between urban tree cover and temperature, as a function of spatial scale. Shown on the Y-axis is the T-value of the parameter, with greater absolute values (farther from zero on the y-axis) having greater explanatory power. We display the trend for maximum summer daily temperature (red), minimum summer daily temperature (blue), and mean summer daily temperature (black) (TIFF 20 kb)
Figure S2
The strength of the statistical relationship between developed cover and temperature, as a function of spatial scale. Shown on the Y-axis is the T-value of the parameter, with greater values having greater explanatory power. We display the trend for maximum summer daily temperature (red), minimum summer daily temperature (blue), and summer daily mean temperature (black) (TIFF 20 kb)
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McDonald, R.I., Kroeger, T., Zhang, P. et al. The Value of US Urban Tree Cover for Reducing Heat-Related Health Impacts and Electricity Consumption. Ecosystems 23, 137–150 (2020). https://doi.org/10.1007/s10021-019-00395-5
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DOI: https://doi.org/10.1007/s10021-019-00395-5