An Exploration of the Urban Heat Island Effect and the Efficacy of Policy Change in Addressing its Social Justice Impacts

Personal Statement

I wrote this paper for my English 102 course to explore tree inequity, a social justice topic I am passionate about. Specifically, this paper examines the relationship between inequitable urban forest distribution throughout the United States, Urban Heat Island (UHI) effect, and adverse health outcomes among low-income populations. I hope this paper will help increase awareness of this issue and educate others on favorable solutions.

Abstract

This paper explores the impact of inequitable urban forest cover distribution throughout the United States. Specifically, this paper examines adverse health outcomes associated with the Urban Heat Island (UHI) effect and the social justice implications of this issue. Researchgathered from meta-analyses, scholarly literature, medical journals, and government agencies reveals a need for drastic federal and state policy change. This paper takes the position that government-funded initiatives are most effective in addressing this important social justice issue.

Keywords: Urban Heat Island effect, UHI, urban forest cover, inequity, social justice,
adverse health outcomes, policy

An Exploration of the Urban Heat Island Effect and the Efficacy of Policy Change in Addressing its Social Justice Impacts

Sparkle Veronica Taylor is a mother of two young boys and a resident of one of the hottest neighborhoods in Richmond, VA. Her neighborhood playground distinctly lacks shade and greenery; thus, Sparkle will frequently walk with her children over a mile in temperaturesupwards of 95°F to access a different park. This park, located in a wealthier neighborhood, is shaded by an abundance of trees that provide a cooler and more enjoyable environment for her children to play in (Plumer & Popovich, 2020). In Richmond, neighborhoods like Sparkle’s – the neighborhoods with the highest temperatures – also experience the “…highest rates of heat-related emergency-room visits” (Plumer & Popovich, 2020).

Unfortunately, this story is not unique to Richmond; throughout the United States, there is an inequitable distribution of urban forest cover among low-income and racial minority populations. Studies have found that these inequities contribute to the UHI effect, which results in adverse health outcomes for residents of affected areas. In this paper, I will discuss why new federal and state policies, such as government-funded initiatives, are the most effective solutions to this issue.

The Inequitable Distribution of Urban Forest Cover Throughout the United States
In recent years, considerable discussion about environmental inequity and justice has occurred within both professional and public spheres; as a result, several researchers have sought to analyze the statistical correlation between urban forestry and socioeconomic status with varying results. Gerrish and Watkins (2018) conducted a meta-analysis of those studies that empirically examined the relationship between urban forest cover and socioeconomic determinants. The meta-analysis confirmed evidence of urban forest cover inequity in low-income neighborhoods. In a companion study, Watkins and Gerrish (2018) also found evidence of race-based inequity in urban forest cover. In particular, African-American residents not only experience significant inequity in urban forest cover on private land but also in access to urban forest cover on public land. Overall, findings suggest that there is an inequitable distribution of urban forest cover throughout the United States regarding socioeconomic status and ethnicity.

The Role of Urban Forest Cover in the Urban Heat Island Effect
The UHI effect is a well-researched phenomenon in which urban environments are significantly warmer than rural counterparts (Soltani & Sharifi, 2017). Many factors contribute to the UHI effect, including a lack of greenery (Soltani & Sharifi, 2017). One significant benefit of urban forest cover is the reduction of the UHI effect. According to Knight et al (2021), urban greenspaces, such as tree canopy cover, parks and gardens, grassy areas, and green roofs/walls
effectively lower surface and air temperatures by 1.4°F to 3.6°F. Therefore, areas affected by the inequitable distribution of urban forest cover are less likely to benefit from the cooling effects of urban greenery. As a result, low-income and ethnic minority populations are more likely to be negatively affected by UHIs.

Adverse Health Outcomes Among Residents of Urban Heat Islands
The UHI effect exacerbates excessive heat events, including heat waves. These heat events are known to result in more frequent instances of heat stroke and other heat-related illnesses (Knight et al., 2021). Additionally, the UHI effect contributes to higher overall ambient temperatures in urban spaces. According to Kovats and Hajat (2008), most people are accustomed to an indoor temperature between 63°F and 87°F. Outside this temperature range, people are increasingly at risk of heat-related injury and illness (Kovats & Hajat, 2008). One such heat-related illness is heat stroke, a core body temperature exceeding 103°F, which can result in severe organ damage and failure (Kovats & Hajat, 2008). It is clear that residents of UHIs are more susceptible to such heat-related illnesses as they are more likely to experience ambient temperatures outside of the typical temperature range.

Additionally, certain groups may be more vulnerable to heat-related illness than others. Older adults, those with metabolic disorders such as diabetes, those with cardiovascular or cerebrovascular disorders, institutionalized persons, outdoor workers, and those experiencing homelessness are a few of the populations that should exercise extreme caution during excessive heat events (Kovats & Hajat, 2008). Many of these populations are also likely to be affected by UHIs as they may share determinants of low socioeconomic status.

Another crucial factor to consider is the concentration of allergens/air pollutants. According to Korzeniowska et al. (2021), “Urbanized UHI areas are characterized by elevated ambient temperatures, increased concentrations of carbon monoxide, carbon dioxide, sulfur dioxide, nitrogen dioxide, as well as increased concentrations of PM and ozone causing an increasing in allergen production.” The increase in pollutants within UHIs is no coincidence. The United States Environmental Protection Agency (2014) explains that elevated temperatures increase the demand for electrical air conditioning, particularly in summer. Most electrical plants utilize fossil fuels to produce electricity. These fossil fuels are known to emit greenhouse gasses and other air pollutants. Additionally, elevated temperatures are known to increase ground-level ozone formation. All these allergens and air pollutants are known to cause health problems and
accelerate the onset of allergies (Korzeniowska et al., 2021).

The Efficacy of Policy Change in Addressing Social Justice Impacts

Current inequities in urban forest cover are closely connected to unjust historical policies such as redlining. Redlining was a historical practice of the federal Home Owner’s Loan Corporation (HOLC) in which the government agency labeled predominantly Black neighborhoods as “risky investments” (Locke et al., 2021; Plumer & Popovich, 2020). A recent analysis of thirty-seven metropolitan areas throughout the United States found that areas ranked “grade D” by the HOLC had almost half as much urban forest cover as compared to areas ranked “grade A” (Locke et al., 2021). Areas labeled “grade D” typically had a significant population of minority residents, whereas areas marked “grade A” were most often populated by upper-middle-class white Americans (Locke et al., 2021). Overall, the study found that “The ranking system used by the Home Owner’s Loan Corporation to assess loan risk in the 1930s parallels the rank order of average percent tree canopy cover today” (Locke et al., 2021).

This correlation is due to myriad factors, including a lack of financial investment and political influence in these redlined neighborhoods. Locke et al. (2021) explain that “Redlined, African American neighborhoods of East and West Baltimore, graded D in the HOLC system, had overcrowded and poor quality housing… These denser, D-graded areas had less available space for trees and tree planting, while A-graded areas consisting of single-family homes on larger lots could maintain, grow and plant additional trees.” Additionally, the analysis describes how a lack of generational and accumulated wealth in grade-D areas prevented residents from investing in public funding to be re-invested in new forest cover (Locke et al., 2021).

Taking Action to Reduce the Impact of Inequitable Urban Forest Cover
To rectify these impacts of systemic discrimination, we must enact new and just policies. For instance, in Chicago, IL, local government officials recently approved a forty-six million dollar initiative to plant 75,000 new trees in the most vulnerable neighborhoods throughout the city (Ellis, 2022). So far, the initiative has seen substantial success. With more than 14,000 trees planted in 2022 alone, the city seems to be on target to reach its five-year goal (Ellis, 2022). For local initiatives like these to continue achieving such success, continued government funding is necessary. On April 23, 2023, the Biden-Harris administration announced one billion dollars in grant money to address the inequitable distribution of urban forest cover throughout the United States (U.S. Department of Agriculture, 2023). Hopefully, this federal funding will make it easier for municipalities such as Chicago to continue addressing the unique needs of their communities.

Some may argue that encouraging residents to simply plant trees within their community would be more effective; however, while planting trees within an individual community may be beneficial, attempts are often disorganized and unsuccessful in addressing the underlying cause of inequity in urban forest cover. According to Lincoln Larson, an associate professor of parks, recreation, and tourism management at the North Carolina State College of Natural Resources, local tree-planting programs and initiatives often fail to adequately involve the populations most affected by urban forest cover inequity (as cited in Moore, 2023). Efforts to increase urban forest cover are typically concentrated in areas with larger lot sizes, greater home values, and pre-existing forest cover (Yeager et al., 2023). Additionally, planting and establishing new tree cover is no easy feat. Consider the Chicago initiative mentioned earlier; there is a reason this 46-million-dollar program requires such a large budget. Facilitating new urban forest growth is not as simple as planting a few young saplings. It is an extensive process that includes regular watering for the first three years, locating appropriate spaces to place new growth, and ensuring proper diversity in tree species to prevent overplanting (Ellis, 2022). These tasks can be arduous to achieve; for instance, many neighborhoods needing new forest cover may have limited space for new tree growth due to decades of redlining. Not to mention, water can be an expensive resource that not everyone can afford to spend on watering trees. Even in Chicago, leaders worry that $46 million is too little. The vice president of the tree-planting initiative states that she is “concerned… [the] contract may not cover all the costs of ensuring the trees survive their first couple of years” (Ellis, 2022). Considering the underlying causes of inequity in urban forest cover and the high expenses to retrofit historically overlooked communities, it is not enough to plant a few trees within a local community. Instead, cities must advocate for federal and state
policies that provide adequate funding for larger initiatives.

In conclusion, there is proven inequity in access to urban forest cover throughout neighborhoods in the United States. This inequity contributes to the UHI effect which is known to cause adverse health outcomes such as heat-related illness and atopic disease. This issue has resulted from inequitable historical policies and practices, including redlining. As such, the most effective solution is to create new policies that address the inequitable distribution of urban forest
cover.

References

Bobrowska-Korzeniowska, M., Jerzyńska, J., Polańska, K., Kaleta, D., Stelmach, I., Kunert, A., & Stelmach, W. (2021). The effect of air pollution on the respiratory system in preschool children with contribution of urban heat islands and geographic data – the aim of the study and methodological assumptions. International Journal of Occupational Medicine and Environmental Health, 34(4), 453–460. https://doi.org/10.13075/ijomeh.1896.01651

Ellis, M. (2022, November 13). Chicago says it’s on track to plant 15,000 trees, 1st step in fixing disparities. Chicago Tribune. https://www.chicagotribune.com/news/environment/ct-our-roots-chicago-tree-ambassadors-20221112-4ihmpwqbcfcubismoihypi4dmm-story.html

Gerrish, E., & Watkins, S. L. (2018). The relationship between urban forests and income: A meta-analysis. Landscape and Urban Planning, 170, 293–308. https://doi.org/10.1016/j.landurbplan.2017.09.005

Knight, T., Price, S., Bowler, D., Hookway, A., King, S., Konno, K., & Richter, R. L. (2021). How effective is “greening” of urban areas in reducing human exposure to ground-level ozone concentrations, UV exposure and the “urban heat island effect”? An updated systematic review. Environmental Evidence, 10(1), 1–38. https://doi.org/10.1186/s13750-021-00226-y

Kovats, R. S., & Hajat, S. (2008). Heat stress and public health: A critical review. Annual Review of Public Health, 29(1), 41–55. https://doi.org/10.1146/annurev.publhealth.29.020907.090843

Locke, D. H., Hall, B., Grove, J. M., Pickett, S. T. A., Ogden, L. A., Aoki, C., Boone, C. G., & O’Neil-Dunne, J. P. M. (2021). Residential housing segregation and urban tree canopy in 37 US Cities. Npj Urban Sustainability, 1(1), 1–9.
https://doi.org/10.1038/s42949-021-00022-0

Moore, A. (2023, June 14). Urban tree planting is booming, just not In low-income and minority neighborhoods. College of Natural Resources News. https://cnr.ncsu.edu/news/2023/06/urban-tree-planting-equity/

Plumer, B., & Popovich, N. (2020, August 24). How decades of racist housing policy left neighborhoods sweltering. The New York Times. https://www.nytimes.com/interactive/2020/08/24/climate/racism-redlining-cities-global-
warming.html

Soltani, A., & Sharifi, E. (2017). Daily variation of urban heat island effect and its correlations to urban greenery: A case study of Adelaide. Frontiers of Architectural Research, 6(4), 529–538. https://doi.org/10.1016/j.foar.2017.08.001

U.S. Department of Agriculture. (2023, April 12). Biden-Harris administration announces historic funding to expand access to trees and green spaces in disadvantaged urban communities. www.usda.gov. https://www.usda.gov/media/press-releases/2023/04/12/biden-harris-administration-announces-historic-funding-expand

United States Environmental Protection Agency. (2014, June 17). Heat island impacts. US EPA. https://www.epa.gov/heatislands/heat-island-impacts

Watkins, S. L., & Gerrish, E. (2018). The relationship between urban forests and race: A meta-analysis. Journal of Environmental Management, 209, 152–168. https://doi.org/10.1016/j.jenvman.2017.12.021

Yeager, R., Browning, M. H.E.M. Browning, Breyer, E., Ossola, A., Larson, L. R., Riggs, D. W., Rigolon, A. Chandler, C., Fleischer, D., Keith, R. J., Walker, K. L., Hart, J. L., Smith, T., & Bhatnagar, A. (2023). Greenness and equity: Complex connections between intra-neighborhood contexts and residential tree planting implementation. Environment International, 176, 107955–107955. https://doi.org/10.1016/j.envint.2023.107955