Urban heat inequity

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Urban heat inequity, also termed thermal inequity, is an unequal distribution of heat in urban areas or neighborhoods within them, which causes disproportionate impacts to people living in those communities. Unequal threat of heat stress in urban environments is often correlated with differences in demographics, including racial and ethnic background, income, education level, and age. [1] While the general impacts of urban heat inequity depend on the city studied, negative effects typically act on historically marginalized communities. [1] The idea is closely tied to the urban heat island effect, where a major cause to urban heat inequity is increased urbanization. [2]

Contents

Observations

There is a correlation in the U.S. between ethnicity and exposure to UHIs. Within most U.S. cities, people of color are more likely to live in areas of high Surface Urban Heat Island Intensity than white people in the same cities. According to a study by climatologist Angel Hsu and colleagues, "the average person of color lives in a census tract with higher SUHI intensity than non-Hispanic whites in all but 6 of the 175 largest urbanized areas" in the U.S. [3]

Economic status also plays a role in the human effects on UHIs. Not only are people of lower economic classes more likely to live in UHIs, but they are also less likely to be able to afford commodities such as air conditioning. Like the correlation between SUHI intensity and ethnicity, a similar pattern can be seen when comparing households under the poverty line against those with an income more than double the poverty line. [3]

UHIs can have particularly strong effects on African Americans with chronic diseases. African Americans have higher rates of various chronic diseases, such as asthma and diabetes, than the general population. Per Professor Pamela Jackson and colleagues, these diseases can be exacerbated by extreme heat, leading to health problems such as hypertension or stroke. [4]

On a global scale, there are discrepancies in the effects of UHIs in different regions of the world. While overall heat exposure is increasing worldwide, its effects have increased faster in the Global South in recent decades, per a study by Professor Kanging Huang and colleagues. [5]

The disproportionate impact of UHIs on the Global South exacerbates already occurring environmental injustices. Because many countries in the equator are naturally hot and humid, these areas are particularly susceptible to the effects of UHIs. One World Bank study has found a 7.0° disparity between the hottest and coolest neighborhoods in Bandung, Indonesia. [6]

Researchers have also noted that the spread of impervious surfaces, such as concrete, tar, and asphalt, is correlated with neighborhoods of low socioeconomic status across various U.S. cities and states. [7] The presence of these materials serves as a predictor of "intra-urban variation in temperature".

Causes

Increased urbanization

Increased urbanization is a major leading cause for increased urban heat risks, as it replaces vegetated areas with impervious surfaces and concentrates people into smaller land areas. [2]

Spatial distribution

Historic urbanization processes, such as redlining in the United States, have lasting impacts on land use and may perpetuate disparities in urban heat through unequal distribution of vegetation. [1] [8] Access to healthcare, public transportation, adequate housing, and reliable energy typically govern disparities to heat, of which many of these communities may lack access to. [8] Such differences in spatial distribution leave certain, localized neighborhood at risk for micro urban heat islands. [9] Socially vulnerable groups are known to live in more densely populated areas with little vegetation that in turn have higher threats to heat exposure and often have adapting to and mitigation their exposure. [9]

Housing conditions

Housing conditions are a factor that contributes to urban heat inequity. Living on the top-floor, having a home with a dark roof, and poor insulation exacerbate heating conditions during hot weather. [10] Lower income individuals may also not have access to air-conditioning or be unable to afford the increased electricity usage. [10] In condensed cities, opening the windows for airflow and cooler air could introduce air pollution and odor into the home. [10] High-density housing is Asia often has constraints on building updates that promote cooling. [10]

Space poverty

Another contributor to inequality is space poverty, which refers to a significantly reduced indoor residential space in a home. [10] Space poverty is a significant issue in Hong Kong, where low-income individuals live in extremely small, sub-divided units, which has led to overcrowding and indoor air pollution. [10] The units promote little movement, and all furniture, kitchen appliances, and bathroom necessities must fit into one sub-divided room. [10] These units are typically developed from derelict buildings that have poor ventilation and less access to proper space cooling. [10] High-density housing is Asia often has constraints on building updates that promote cooling, and residents often lack the space and authority to complete any improvements to their condition. [10] These residents typically seek out adequate third places, such as libraries, parks, and cafés, to access proper cooling and space. [10]

Impacts

Heat stress vulnerability

Heat stress vulnerability refers to an individual's predisposition, typically due to demographic factors, to be negatively impacted by heat. [10] The measurement takes into account daily routines, location, sensitivity due to demographic factors, including age. [10] Some demographic groups known to have higher heat stress vulnerability include the elderly, women, children, low-income households, and those who are chronically ill. [10] Elderly populations are included because they are often unable to regular their body temperatures and typically have pre-existing medical conditions that make them more susceptible to heat. [10] Children are also sensitive to increased heat, which may cause stress on their developing bodies. [10] Intensified indoor heat causes stress on the mind and body and strains domestic relations. [10]

Potential Solutions

Urban green infrastructure

Urban green infrastructure (UGI) are integrated networks of green spaces in cities and are developed in both private and public areas of the city. [1] Examples of UGI include urban parks with trees and shrub cover, rows of trees along a street, private gardens, rooftop gardens, and other green space throughout a city. [10] Properly utilized UGI promotes more equitable heat distribution, where improper usage only perpetuates heat inequity. [1] UGI provides shading and evapotranspiration, which reduces both air and land temperatures. [1] Therefore, a lack of UGI in marginalized communities reduces the land's temperature regulating capabilities promotes heat inequity. [1] UGI is widely recognized as an efficient, sustainable, and non-controversial solution to heat inequity. [1]

See also

Related Research Articles

<span class="mw-page-title-main">Urban heat island</span> Urban area that is significantly warmer than its surrounding rural areas

Urban areas usually experience the urban heat island (UHI) effect, that is, they are significantly warmer than surrounding rural areas. The temperature difference is usually larger at night than during the day, and is most apparent when winds are weak, under block conditions, noticeably during the summer and winter. The main cause of the UHI effect is from the modification of land surfaces while waste heat generated by energy usage is a secondary contributor. A study has shown that heat islands can be affected by proximity to different types of land cover, so that proximity to barren land causes urban land to become hotter and proximity to vegetation makes it cooler. As a population center grows, it tends to expand its area and increase its average temperature. The term heat island is also used; the term can be used to refer to any area that is relatively hotter than the surrounding, but generally refers to human-disturbed areas. Urban areas occupy about 0.5% of the Earth's land surface but host more than half of the world's population.

<span class="mw-page-title-main">Urbanization</span> Process of population movement to cities

Urbanization is the population shift from rural to urban areas, the corresponding decrease in the proportion of people living in rural areas, and the ways in which societies adapt to this change. It can also mean population growth in urban areas instead of rural ones. It is predominantly the process by which towns and cities are formed and become larger as more people begin living and working in central areas.

<span class="mw-page-title-main">Urban ecology</span> Scientific study of living organisms

Urban ecology is the scientific study of the relation of living organisms with each other and their surroundings in an urban environment. An urban environment refers to environments dominated by high-density residential and commercial buildings, paved surfaces, and other urban-related factors that create a unique landscape. The goal of urban ecology is to achieve a balance between human culture and the natural environment.

<span class="mw-page-title-main">Urban forestry</span> Land use management system in which trees or shrubs are cared or protected for well-being

Urban forestry is the care and management of single trees and tree populations in urban settings for the purpose of improving the urban environment. Urban forestry involves both planning and management, including the programming of care and maintenance operations of the urban forest. Urban forestry advocates the role of trees as a critical part of the urban infrastructure. Urban foresters plant and maintain trees, support appropriate tree and forest preservation, conduct research and promote the many benefits trees provide. Urban forestry is practiced by municipal and commercial arborists, municipal and utility foresters, environmental policymakers, city planners, consultants, educators, researchers and community activists.

<span class="mw-page-title-main">Living street</span> Traffic calming in spaces shared between road users

A living street is a street designed with the interests of pedestrians and cyclists in mind by providing enriching and experiential spaces. Living streets also act as social spaces, allowing children to play and encouraging social interactions on a human scale, safely and legally. Living streets consider all pedestrians granting equal access to elders and those who are disabled. These roads are still available for use by motor vehicles; however, their design aims to reduce both the speed and dominance of motorized transport. The reduction of motor vehicle dominance creates more opportunities for public transportation.

The climate in urban areas differs from that in neighboring rural areas, as a result of urban development. Urbanization greatly changes the form of the landscape, and also produces changes in an area's air. The study of urban climate is urban climatology.

Urban climatology is the study of urban climate. It is a branch of climatology that concerns interactions between urban areas and the atmosphere, the effects they have on one another, and the varying spatial and temporal scales at which these processes occur.

<span class="mw-page-title-main">Social determinants of health</span> Economic and social conditions that influence differences in health status

The social determinants of health (SDOH) are the economic and social conditions that influence individual and group differences in health status. They are the health promoting factors found in one's living and working conditions, rather than individual risk factors that influence the risk or vulnerability for a disease or injury. The distribution of social determinants is often shaped by public policies that reflect prevailing political ideologies of the area.

<span class="mw-page-title-main">Energy poverty</span> Lack of access to energy services such as electricity and heating

In developing countries and some areas of more developed countries, energy poverty is lack of access to modern energy services in the home. In 2022, 759 million people lacked access to consistent electricity and 2.6 billion people used dangerous and inefficient cooking systems. Their well-being is negatively affected by very low consumption of energy, use of dirty or polluting fuels, and excessive time spent collecting fuel to meet basic needs.

<span class="mw-page-title-main">Greening</span> Process of incorporating more environmentally friendly behaviors or systems

Greening is the process of transforming living environments, and also artifacts such as a space, a lifestyle or a brand image, into a more environmentally friendly version. The act of greening generally involves incorporating more environmentally friendly systems into one's environment, such as the home, work place, and general lifestyle.

Unnatural Causes: Is Inequality Making Us Sick? is a four-hour documentary series, broadcast nationally in the United States on PBS in spring 2008, that examines the role of social determinants of health in creating health inequalities/health disparities in the US. Based on extensive research by a wide variety of academics, public health experts and medical practitioners, the seven-part series explores how class and racism can have greater impacts on one's health outcomes than genetics or personal behavior.

<span class="mw-page-title-main">Urban green space</span> Green area planned in an urban location

In land-use planning, urban green space is open-space areas reserved for parks and other "green spaces", including plant life, water features - also referred to as blue spaces - and other kinds of natural environment. Most urban open spaces are green spaces, but occasionally include other kinds of open areas. The landscape of urban open spaces can range from playing fields to highly maintained environments to relatively natural landscapes.

<span class="mw-page-title-main">Urban resilience</span> Ability of a city to function after a crisis

Urban resilience has conventionally been defined as the "measurable ability of any urban system, with its inhabitants, to maintain continuity through all shocks and stresses, while positively adapting and transforming towards sustainability".

The social determinants of health in poverty describe the factors that affect impoverished populations' health and health inequality. Inequalities in health stem from the conditions of people's lives, including living conditions, work environment, age, and other social factors, and how these affect people's ability to respond to illness. These conditions are also shaped by political, social, and economic structures. The majority of people around the globe do not meet their potential best health because of a "toxic combination of bad policies, economics, and politics". Daily living conditions work together with these structural drivers to result in the social determinants of health.

Arline Geronimus wrote about the weathering hypothesis the early 1990s to account for health disparities of newborn babies and birth mothers due to decades and generations of racism and social, economic, and political oppression. It is well documented that people of color and other marginalized communities have worse health outcomes than white people. This is due to multiple stressors including prejudice, social alienation, institutional bias, political oppression, economic exclusion, and racial discrimination. The weathering hypothesis proposes that the cumulative burden of these stressors as individuals age is "weathering", and the increased weathering experienced by minority groups compared to others can account for differences in health outcomes. In recent years, social scientists investigated the biological plausibility of the weathering hypothesis in studies evaluating the physiological effects of social, environmental and political stressors among marginalized communities. The weathering hypothesis is more widely accepted as a framework for explaining health disparities on the basis of differential exposure to racially based stressors. Researchers have also identified patterns connecting weathering to biological phenomena associated with stress and aging, such as allostatic load, epigenetics, telomere shortening, and accelerated brain aging.

<span class="mw-page-title-main">Blue space</span> Areas dominated by surface waterbodies

In urban planning and design, blue space comprises areas dominated by surface waterbodies or watercourses. In conjunction with greenspace, it may help in reducing the risks of heat-related illness from high urban temperatures . Substantial urban waterbodies naturally exist as integral features of the geography of many cities because of their historical development, for example the River Thames in London.

<span class="mw-page-title-main">Climate change and cities</span>

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<span class="mw-page-title-main">Heat dome</span> Weather phenomenon

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Biological inequity, also known as biological inequality, refers to the “systematic, unfair, and avoidable stress-related biological differences which increase risk of disease, observed between social groups of a population”. The term developed by Centric Lab aims to unify societal factors with the biological underpinnings of health inequities – the unfair and avoidable differences in health status and risks between social groups of a population — such that these inequalities can be investigated in a holistic manner.

Urban forest inequity, also known as shade inequity or tree canopy inequity, is the inequitable distribution of trees, with their associated benefits, across metropolitan areas. This phenomenon has a number of follow-on effects, including but not limited to measurable impacts on faunal biodiversity and the urban heat island effect. Urban heat inequity occurs when intra-urban heat islands, with their associated negative physical and emotional health consequences, are more common and more intense in lower-income communities.

References

  1. 1 2 3 4 5 6 7 8 Chen, Peng (January 2024). "Inequality in heat: The role of spatial patterns of urban green infrastructure". Urban Climate. 53: 101820. Bibcode:2024UrbCl..5301820C. doi:10.1016/j.uclim.2024.101820.
  2. 1 2 Lin, Jian; Zhang, Hongsheng; Chen, Min; Wang, Qiang (May 2023). "Socioeconomic disparities in cooling and warming efficiencies of urban vegetation and impervious surfaces". Sustainable Cities and Society. 92: 104464. doi:10.1016/j.scs.2023.104464. ISSN   2210-6707.
  3. 1 2 Hsu, Angel; Sheriff, Glenn; Chakraborty, Tirthankar; Manya, Diego (25 May 2021). "Disproportionate exposure to urban heat island intensity across major US cities". Nature Communications. 12 (1): 2721. Bibcode:2021NatCo..12.2721H. doi:10.1038/s41467-021-22799-5. PMC   8149665 . PMID   34035248.
  4. ↑ Jackson, Pamela; Larkin, Danielle; Kinnie, Kiari R.; Aroke, Edwin N. (July 2022). "Heat Islands and Chronic Disease: Could African Americans Be More Vulnerable to Heat-Related Health Impacts?". Journal of National Black Nurses' Association. 33 (1): 33–39. PMC   10387230 . PMID   37520179.
  5. ↑ Huang, Kangning; Li, Xia; Liu, Xiaoping; Seto, Karen C (November 2019). "Projecting global urban land expansion and heat island intensification through 2050". Environmental Research Letters. 14 (11): 114037. Bibcode:2019ERL....14k4037H. doi: 10.1088/1748-9326/ab4b71 .
  6. ↑ "Unlivable: What the Urban Heat Island Effect Means for East Asia's Cities". World Bank. Retrieved 2024-05-02.
  7. ↑ Jesdale, Bill M.; Morello, -Frosch Rachel; Cushing, Lara (2013-07-01). "The Racial/Ethnic Distribution of Heat Risk–Related Land Cover in Relation to Residential Segregation". Environmental Health Perspectives. 121 (7): 811–817. doi:10.1289/ehp.1205919. PMC   3701995 . PMID   23694846.
  8. 1 2 Keith, Ladd; Gabbe, C.J.; Schmidt, Erika (2023-09-03). "Urban heat governance: examining the role of urban planning". Journal of Environmental Policy & Planning. 25 (5): 642–662. Bibcode:2023JEPP...25..642K. doi:10.1080/1523908X.2023.2244446. ISSN   1523-908X.
  9. 1 2 Mitchell, Bruce Coffyn; Chakraborty, Jayajit (2018-08-03). "Exploring the relationship between residential segregation and thermal inequity in 20 U.S. cities". Local Environment. 23 (8): 796–813. Bibcode:2018LoEnv..23..796M. doi:10.1080/13549839.2018.1474861. ISSN   1354-9839.
  10. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 Lo, Alex Y.; Jim, C.Y.; Cheung, Pui Kwan; Wong, Gwendolyn K.L.; Cheung, Lewis T.O. (August 2022). "Space poverty driving heat stress vulnerability and the adaptive strategy of visiting urban parks". Cities. 127: 103740. doi:10.1016/j.cities.2022.103740. ISSN   0264-2751.
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