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Liu S, Smith-Greenaway E. Racial and ethnic minorities disproportionately exposed to extreme daily temperature variation in the United States. PNAS NEXUS 2024; 3:pgae176. [PMID: 38774391 PMCID: PMC11107375 DOI: 10.1093/pnasnexus/pgae176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Accepted: 04/18/2024] [Indexed: 05/24/2024]
Abstract
In the history of Homo sapiens, well-populated habitats have featured relatively stable temperatures with generally small daily variations. As the global population is increasingly residing in highly disparate climates, a burgeoning literature has documented the adverse health effects of single-day and day-to-day variation in temperature, raising questions of inequality in exposure to this environmental health risk. Yet, we continue to lack understanding of inequality in exposure to daily temperature variation (DTV) in the highly unequal United States. Using nighttime and daytime land surface temperature data between 2000 and 2017, this study analyzes population exposure to long-term DTV by race and ethnicity, income, and age for the 50 states and the District of Columbia. The analysis is based on population-weighted exposure at the census-tract level. We find that, on average, non-White (especially Black and Hispanic) and low-income Americans are exposed disproportionately to larger DTV. Race-based inequalities in exposure to DTV are larger than income-based disparities, with inequalities heightened in the summer months. In May, for example, the DTV difference by race and ethnicity of 51 states is between 0.20 and 3.01 °C (up to 21.0%). We find that younger populations are, on average, exposed to larger DTV, though the difference is marginal.
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Affiliation(s)
- Shengjie Liu
- Spatial Sciences Institute, Dornsife College of Letters, Arts and Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Emily Smith-Greenaway
- Department of Sociology, Dornsife College of Letters, Arts and Sciences, University of Southern California, Los Angeles, CA 90089, USA
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Ming Y, Liu Y, Liu X, Tian Z. Demographic disparity in diurnal surface urban Heat Island exposure across local climate zones: A case study of Chongqing, China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 923:171203. [PMID: 38428601 DOI: 10.1016/j.scitotenv.2024.171203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 02/06/2024] [Accepted: 02/21/2024] [Indexed: 03/03/2024]
Abstract
Surface urban heat island (SUHI) exposure significantly harms human health during rapid urbanization. Identifying the areas and demographic groups under high SUHI exposure is critical for mitigating heat-related hazards. However, despite broad concern in US-European countries, rare studies discuss the diurnal SUHI exposure of demographic subgroups across Local Climate Zones (LCZs) in Chinese cities. Therefore, taking Chongqing as the case study, we measured the diurnal SUHI exposure of demographic subgroups (e.g., gender, age, and income) across different LCZs (compact, open, and sparsely-built zones) by coupling the ECOSTRESS data and mobile phone signaling data. The results indicated that Chongqing's compact high/middle-rise zones suffered a higher SUHI exposure due to high land surface temperature (LST) and a larger size of population than open zones. Despite a relatively low population density, extremely high LST in compact low-rise zones (e.g., industrial parks) contributes to considerable accumulated SUHI exposure. The SUHI exposure risk exhibited the differences between daytime and nighttime, resulting from SUHI variation and population flow. The demographic analysis showed that Chongqing's demographic subgroups are exposed disproportionately to SUHI. Elderly groups suffered relatively high exposure in compact high-rise zones. Low-incomers witnessed a high exposure in open zones. These findings call for alleviating SUHI exposure risk by targeting vulnerable groups and high-intensity exposure areas.
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Affiliation(s)
- Yujia Ming
- School of Management Science and Real Estate, Chongqing University, Chongqing 400045, PR China.
| | - Yong Liu
- School of Management Science and Real Estate, Chongqing University, Chongqing 400045, PR China.
| | - Xue Liu
- School of Geographic Sciences, East China Normal University, Shanghai 200241, PR China.
| | - Zongshun Tian
- School of Management Science and Real Estate, Chongqing University, Chongqing 400045, PR China.
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Zeng P, Shi D, Helbich M, Sun F, Zhao H, Liu Y, Che Y. Gender disparities in summer outdoor heat risk across China: Findings from a national county-level assessment during 1991-2020. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 921:171120. [PMID: 38382599 DOI: 10.1016/j.scitotenv.2024.171120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 01/21/2024] [Accepted: 02/18/2024] [Indexed: 02/23/2024]
Abstract
Increasing anthropogenic global warming has emerged as a significant challenge to human health in China, as extreme heat hazards increasingly threaten outdoor-exposed populations. Differences in thermal comfort, outdoor activity duration, and social vulnerability between females and males may exacerbate gender inequalities in heat-related health risks, which have been overlooked by previous studies. Here, we combine three heat hazards and outdoor activity duration to identify the spatiotemporal variation in gender-specific heat risk in China during 1991-2020. We found that females' heat risk tends to be higher than that of males. Gender disparities in heat risk decrease in southern regions, while those in northern regions remain severe. Males are prone to overheating in highly urbanized areas, while females in low urbanized areas. Males' overheating risk is mainly attributed to population clustering associated with prolonged outdoor activity time and skewed social resource allocation. In contrast, females' overheating risk is primarily affected by social inequalities. Our findings suggest that China needs to further diminish gender disparities and accelerate climate adaptation planning.
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Affiliation(s)
- Peng Zeng
- School of Ecological and Environmental Sciences, Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, Institute of Eco-Chongming (IEC), East China Normal University, Shanghai 200241, China; Department of Human Geography and Spatial Planning, Faculty of Geosciences, Utrecht University, Utrecht CS 3584, the Netherlands
| | - Dachuan Shi
- Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong
| | - Marco Helbich
- Department of Human Geography and Spatial Planning, Faculty of Geosciences, Utrecht University, Utrecht CS 3584, the Netherlands
| | - Fengyun Sun
- School of Environmental and Geographical Sciences, Shanghai Normal University, Shanghai 200234, China
| | - Hongyu Zhao
- School of Architecture and Planning, Jilin Jianzhu University, No.5088, Xincheng Road, Nanguan District, Changchun 130118, China
| | - Yaoyi Liu
- School of Ecological and Environmental Sciences, Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, Institute of Eco-Chongming (IEC), East China Normal University, Shanghai 200241, China
| | - Yue Che
- School of Ecological and Environmental Sciences, Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, Institute of Eco-Chongming (IEC), East China Normal University, Shanghai 200241, China.
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Locke DH, Baker M, Alonzo M, Yang Y, Ziter CD, Murphy-Dunning C, O'Neil-Dunne JP. Variation the in relationship between urban tree canopy and air temperature reduction under a range of daily weather conditions. Heliyon 2024; 10:e25041. [PMID: 38352758 PMCID: PMC10862499 DOI: 10.1016/j.heliyon.2024.e25041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 01/18/2024] [Accepted: 01/18/2024] [Indexed: 02/16/2024] Open
Abstract
Mitigating heat is a vital ecosystem service of trees, particularly with climate change. Land surface temperature measures captured at a single time of day (in the morning) dominate the urban heat island literature. Less is known about how local tree canopy and impervious surface regulate air temperature throughout the day, and/or across many days with varied weather conditions, including cloud cover. We use bike-mounted air temperature sensors throughout the day in New Haven, Connecticut, USA, from 2019 to 2021 and generalized additive mixed models across 156 rides to estimate the daily variation in cooling benefits associated with tree canopy cover, and warming from impervious surface cover in 90 m buffers surrounding bike observations. Cooling is inferred by subtracting the bicycle-observed temperature from a reference station. The cooling benefits from tree canopy cover were strongest in the midday (11:00-14:00, -1.62 °C), afternoon (14:00-17:00, -1.19 °C), and morning (8:00-11:00, -1.15 °C) on clear days. The cooling effect was comparatively smaller on cloudy mornings -0.92 °C and afternoons -0.51 °C. Warming from impervious surfaces was most pronounced in the evening (17:00-20:00, 1.11 °C) irrespective of clouds, and during cloudy nights (20:00-23:00) and cloudy mornings 1.03 °C 95 % CI [1.03, 1.04]. Among the hottest observed days (top 25th percentile of reference station daily maxima), tree canopy was associated with lower temperatures on clear afternoons -1.78 °C [-1.78, -1.78], cloudy midday -1.17 °C [-1.19, -1.15], clear midday -1.12 °C [-1.12, -1.11]. We add a broader spectrum of weather conditions by explicitly including clouds, and greater temporal resolution by measuring throughout the day to bike-based urban heat research. Future mobile sampling campaigns may broaden the spatial extent with more environmental variation, representing an opportunity for public science and engagement.
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Affiliation(s)
- Dexter Henry Locke
- USDA Forest Service, Northern Research Station, Baltimore Field Station, Suite 350, 5523 Research Park Drive, Baltimore, MD, 21228, USA
| | - Matthew Baker
- Department of Geography & Environmental Systems, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD, 21250, USA
| | - Michael Alonzo
- Department of Environmental Science, American University, Hall of Science – 328 4400 Massachusetts Ave, NW Washington, DC, 20016-8014, USA
| | - Yichen Yang
- Yale School of the Environment, Environmental Science Center, Room 300, 21 Sachem Street, New Haven, CT, 06511, USA
| | - Carly D. Ziter
- Department of Biology, Concordia University, 7141 Sherbrooke West, Montreal, Quebec, H4B 1R6, Canada
| | - Colleen Murphy-Dunning
- Hixon Center Urban Sustainabilitiy, Urban Resources Initiative, Yale School of the Environment, 301 Prospect St #1, New Haven, CT, 06511, USA
| | - Jarlath P.M. O'Neil-Dunne
- Spatial Analysis Lab, Rubenstein School of Environment and Natural Resources, University of Vermont, 81 Carrigan Drive, Burlington, VT, 05405, USA
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Ju Y, Dronova I, Rodriguez DA, Bakhtsiyarava M, Farah I. Recent greening may curb urban warming in Latin American cities of better economic conditions. LANDSCAPE AND URBAN PLANNING 2023; 240:None. [PMID: 38046954 PMCID: PMC10570748 DOI: 10.1016/j.landurbplan.2023.104896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 09/04/2023] [Accepted: 09/13/2023] [Indexed: 12/05/2023]
Abstract
Rising temperatures have profound impacts on the well-being of urban residents. However, factors explaining the temporal variability of urban thermal environment, or urban warming, remain insufficiently understood, especially in the Global South. Addressing this gap, we studied the relationship between city-level economic conditions and urban warming, and how urban green space mediated this relationship, focusing on 359 major Latin American cities between 2001 and 2022. While effect sizes varied by economic and temperature measures used, we found that better economic conditions were associated with lower baseline greenness in 2011, which contributed to faster warming. There was modest evidence that this faster warming associated with lower baseline greenness and improved economic conditions was partially offset by cooling from recent greening (2001-2022) in cities of better economic conditions. This offset was more evident in arid cities. Together, these findings provide insights into the urban warming mechanism manifested through the effect of economic conditions on urban green space, for Latin American cities and other high-density cities transforming in a similar context.
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Affiliation(s)
- Yang Ju
- School of Architecture and Urban Planning, Nanjing University, Rm. 810, Jianliang Bldg., No. 22 Hankou Rd., Nanjing, China
| | - Iryna Dronova
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, USA
- Department of Landscape Architecture and Environmental Planning, University of California, Berkeley, USA
| | - Daniel A. Rodriguez
- Department of City and Regional Planning, University of California, Berkeley, USA
- Institute of Transportation Studies, University of California, Berkeley, USA
| | - Maryia Bakhtsiyarava
- Institute of Urban and Regional Development, University of California, Berkeley, USA
| | - Irene Farah
- Department of City and Regional Planning, University of California, Berkeley, USA
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