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Legal Approaches to Alleviating the Effects of Extreme Heat Disparities in Cities

May 05, 2022

Image of a heat map of Philadelphia, with the article's title across the top.
Image of a heat map of Philadelphia, with the article’s title across the top.
Charlotte Edelstein L’23

Charlotte Edelstein holds a B.A. from Haverford College. She is an Online Editor for the Journal of Law and Social Change, Vol. 26.

Legal Approaches to Alleviating the Effects of Extreme Heat Disparities in Cities


Uncomfortably hot summer days in Philadelphia are nothing new. But as global temperatures rise, periods of extreme heat, particularly in cities, are becoming more common and more dangerous.[1] Cities tend to be hotter than rural areas because the built environment (the human-made aspects) of a city traps heat during the day and keeps the air from cooling overnight, resulting in the “urban heat island effect.”[2] The harmful effects of these rising temperatures are not equally distributed. Across the country, including in Philadelphia, people of color and low-income groups live in the hottest urban neighborhoods.[3]

In Philadelphia, the average temperature from one neighborhood to another can vary by as much as 22º.[4] In addition to higher temperatures, some neighborhoods are more vulnerable to extreme heat because of a lack of access to short-term cooling strategies like home air-conditioning, pools, and air-conditioned public spaces.

There are two ways to confront the unequal distribution of harm from rising temperatures: first, to increase access to short-term cooling strategies for those who live in the hottest neighborhoods, and second, to change the built environment so that the average temperature of those neighborhoods decreases.

The Impact of Heat Exposure & Inequities

Extreme heat can have both health impacts and economic impacts. Because extreme heat will become more common as temperatures rise, it is important to understand who is most likely to suffer from these harms.

Inequity in exposure to extreme heat is not just an issue of comfort. A 2007 paper on environmental policy found that in comparison to other environmental disasters, “heat waves and heat-wave deaths recede quickly from our collective memory” in part because they do not cause property damage and do not generate images of destruction.[5] However, between 2011 and 2020, heat was the largest cause of weather-related deaths in the United States.[6]

Extreme heat can cause heat-related illnesses such as heat exhaustion or stroke,[7] and can exacerbate pre-existing health conditions like asthma and cardiovascular issues.[8] People with chronic medical conditions like heart disease, mental illness, and poor circulation are more vulnerable to heat-related illness because their bodies may be less able to respond to changes in temperature, and prescribed medicines may further negatively affect the body’s ability to regulate its temperature.[9]

The concrete harms caused by extreme heat are not felt equally across neighborhoods. There is a clear connection between exposure to extreme heat and the history of racially discriminatory lending and urban design. As of 2019, in 108 U.S. cities, neighborhoods that were redlined in the 1930s were significantly hotter than other residential areas.[10] As planners continued to transform cities, they placed roadways and large building complexes, both of which increase the ambient temperatures of the neighborhoods around them, in redlined areas.[11]

Along with continued disinvestment, the intentional placement of these urban features within low-income communities of color means that “current maps of intra-urban heat echo the legacy of past planning policies.”[12] As one person working on these issues noted, “Even people who don’t believe institutionalized racism are struck when we show them these maps.”[13]

Higher temperatures also reinforce the economic inequity caused by past planning policies, as high energy and health bills place financial pressure on these neighborhoods’ occupants.[14] Housing conditions may further exacerbate this financial pressure. Philadelphia neighborhoods with high heat vulnerability also tend to be those with older housing, which has maintenance issues that limit the usefulness of heat mitigation strategies.[15] Thus, the households in the hottest neighborhoods have a greater need to cool their homes, but also less efficient means of doing so.

Solutions, Strategies, and Obstacles

Decreasing exposure to the harms of extreme heat requires both increasing access to air conditioning in the home and decreasing the neighborhood’s ambient temperature. To increase access to home air conditioning, residents need to have an air conditioner and the financial ability to use it enough to effectively lower the temperature. Ideally, long-term strategies like tree planting and greening vacant lots would supplement efforts to increase home air conditioning access by lowering ambient temperatures, thus decreasing the need to spend as much on air conditioning. Additionally, these long-term strategies should focus on improving the safety and comfort of those who already live in these neighborhoods, and on avoiding contributions to gentrification.

A. Increasing Safety and Comfort in the Home

In most states the implied warranty of habitability for rental housing requires landlords to provide heat, but not cooling.[16] Arizona is a rare exception: landlords must provide air-conditioning and must repair malfunctioning air-conditioning in a reasonable amount of time.[17] Some Arizona cities have added to this requirement and mandated a maximum temperature for rental housing (for example, in Phoenix the maximum is 86º).[18] Similarly, Montgomery County, Maryland passed a law in 2020 requiring landlords to provide and maintain air conditioning that keeps the residential unit at 80º or below.[19]

As reported in the background of the Montgomery County bill, at the time of its passage only 4% of rental housing in Maryland lacked air conditioning.[20] Similarly, in a survey of one Philadelphia neighborhood 84% of respondents had access to air conditioning, but 77% reported still feeling too hot in their homes.[21] In the same survey, out of residents who said they felt too hot in their homes, 25% said help with utility bills would allow them to stay cooler.[22] These statistics point to the possibility that the largest barrier to air-conditioning may not be acquiring the unit itself, but rather, having one that can sufficiently cool the home without costing an insurmountable amount in utilities.[23]

One common source of financial assistance for heating bills in Pennsylvania is the Low Income Home Energy Assistance Program (LIHEAP).[24] Although states are authorized to use their national LIHEAP grants for heating, cooling, and weatherization, in many states, including Pennsylvania, LIHEAP does not assist with cooling costs.[25] However, the public comments process provides an opportunity to advocate to DHS for LIHEAP coverage of cooling costs.[26]

Another avenue to increase home air conditioning is to focus on public housing. The U.S. Department of Housing and Urban Development (HUD) does not require public housing to have air conditioning.[27] Although local Public Housing Authorities (PHAs) are permitted to calculate utility allowances based in part on climate and weatherization, in housing where the PHA installs air conditioning that the resident can choose to use, HUD instructs the PHA not to include energy used for air-conditioning in the utility allowance.[28]

Thus, in Philadelphia, most PHA tenants who need air conditioning are required to purchase units and pay for the increased energy use.[29] However, some public housing residents may be legally entitled to increased utility subsidies.

In 2005, the District Court of Hawaii certified a class of disabled public housing tenants who sought injunctive relief under the Rehabilitation Act, Americans with Disabilities Act, and Fair Housing Act.[30] Plaintiffs sought to require the Housing Authority to notify disabled tenants of their right to request and the process to obtain higher utility allowance where electric costs were higher because of physician-prescribed medical equipment.[31] The case ended in a settlement, as did a case in Kentucky where a household member had a medically documented need for air-conditioning.[32] These cases demonstrate the possibility of increased utility allowance for some PHA residents, and a possible legal route to ensuring enforcement.

B. Lowering the Ambient Temperature

Outside of private residences, increasing vegetation coverage and decreasing impervious surfaces can help lower the ambient temperature in urban neighborhoods.[33] In Philadelphia, existing greening efforts include a program that distributes free trees[34] and a Water Department program that calculates fees for impervious surfaces and provides credits against these fees for implementation of green infrastructure.[35]

While tree distribution is an effective way to increase shade and carbon sequestration, tree distribution programs may be difficult to implement in neighborhoods where most residents are renters. Many tree distribution programs, including TreePhilly, require requests for trees to come from property owners.[36] This means that tenants of a building with an absentee landlord cannot take advantage of these programs.[37]

One Los Angeles tree distribution program recognized this barrier and decided to focus on planting trees in public areas where they did not need property owners’ consent.[38] However, because of existing infrastructure that was common specifically in low-income neighborhoods, such as underground water mains and overhead powerlines, it was still difficult to plant trees that were big enough to have an impact.[39]

Maintenance of vacant land provides another opportunity to replace impervious surfaces with vegetation in the hottest neighborhoods. A 2014 study of Philadelphia “found that vacant land contributed to elevated temperatures and that the majority of vacant lots were located in temperature hot spots that had higher poverty rates, lower median household income, and employment rates than the remainder of the city.”[40]

Vacant land therefore provides an opportunity to bring vegetation to and decrease the average temperature of the neighborhoods most vulnerable to extreme heat.[41] Unlike temporary “clean and green” strategies that aim to make vacant lots more attractive for redevelopment, increasing vegetation on vacant land for the sake of heat mitigation is a long-term project for the benefit of those who already live in the neighborhood.[42]

However, as the Public Interest Law Center’s Garden Justice Legal Initiative describes, community groups seeking to grow food on public and private vacant land may face logistical roadblocks to long-term access and control of land.[43]

Additionally, greening projects in low-income neighborhoods must consider the risk of displacement through “green gentrification.” Generally, adding greenery to a neighborhood increases property values.[44] Philadelphia has a history of initiating environmental stewardship projects that “green” a neighborhood and, in the process, force low-income Black residents out of their homes.[45] As property values and rents rise and the neighborhood becomes more desirable to higher-income white residents, low-income Black residents are forced out, and the new residents remake the neighborhood to meet their own preferences.[46]

Thus, efforts to decrease ambient temperatures in Philadelphia’s hottest neighborhoods must also work to decrease this risk of displacement. Otherwise, they will counteract the primary goal of decreasing the neighborhood’s temperature in the first place: making the neighborhood more affordable, more comfortable, and safer for the people who already call it home.


Image credit: Charlotte Wagner, Mapping heat vulnerability in Philadelphia, HARVARD UNIVERSITY [ ] (last visited May 3, 2022).

[1] Jeremy S. Hoffman, Vivek Shandas, & Nicholas Pendleton, The Effects of Historical Housing Policies on Resident Exposure to Intra-Urban Heat: A Study of 108 US Urban Areas, 8(1) CLIMATE 1, 1 (2020),

[2] Hamil Pearsall, Staying Cool in the Compact City: Vacant Land and Urban Heating in Philadelphia, Pennsylvania, 79 APPLIED GEOGRAPHY 84, 84 (2017),

[3] Angel Hsu, Glenn Sheriff, Tirthankar Chakraborty, & Diego Manya, Disproportionate Exposure to Urban Heat Island Intensity Across Major US Cities, 12(2721) NATURE COMMC’NS 1, 5 (2021),

[4] Philadelphia Office of Sustainability (OOS), Beat the Heat Hunting Park, 1 (2019), [].

[5] Ann E. Carlson, Heat Waves, Global Warming, and Mitigation, 26 UCLA J. ENV’T. L. & POL’Y 169, 173 (2007).

[6] National Weather Service, Weather Related Fatality and Injury Statistics, [] (last visited Apr. 25, 2022).

[7] Centers for Disease Control and Prevention (CDC), Natural Disasters and Severe Weather: About Extreme Heat, [] (last visited Apr. 25, 2022).

[8] Hoffman et al., supra note 1, at 1.

[9] CDC, supra note 7; Centers for Disease Control and Prevention (CDC), Heat and Older Adults, [] (last visited May 1, 2022).

[10] Hsu et al., supra note 3, at 2.

[11] Hoffman et al., supra note 1, at 10. See also Deborah N. Archer, “White Men’s Roads through Black Men’s Homes”: Advancing Racial Equity through Highway Reconstruction, 73 VAND. L. REV. 1259, 1273-85 (2020) (describing the use of highway systems as segregationist tools).

[12] Hoffman et al., supra note 1, at 9.

[13] Brad Plumer & Nadja Popovich, How Decades of Racist Housing Policy Left Neighborhoods Sweltering, NEW YORK TIMES (Aug. 24, 2020), [].

[14] Hoffman, supra note 1, at 11.

[15] Christopher K. Uejio, Olga V. Wilhelmi, Jay S. Golden, David M. Mills, Sam P. Gulino, & Jason P. Samenow, Intra-urban Societal Vulnerability to Extreme Heat: The Role of Heat Exposure and the Built Environment, Socioeconomics, and Neighborhood Stability, 17 HEALTH AND PLACE 498, 503-04 (2010),

[16] Michael B. Gerrard, Heat Waves: Legal Adaption to the Most Lethal Climate Disaster (So Far), 40 U. ARK. LITTLE ROCK L. REV. 515, 538 (2018).

[17] Ashley M. Gregor, Toward a Legal Standard of Tolerable Heat, 44 COLUM. J. ENV’T L. 479, 517-18 (2019).

[18] Gerrard, supra note 16, at 538-39.

[19] Bill No. 24-19 Concerning: Landlord-Tenant Relations – Obligations of Landlord – Air Conditioning, Montgomery County Council (2020), [].

[20] Action Staff Report: Bill 24-19, at 2, Montgomery County Council (2020), [].

[21] OOS, supra note 4, at 2.

[22] OOS, supra note 4, at 29. The same survey also found that only 4% of respondents who said they limited their use of air conditioning because of the cost had heard of utility assistance programs. Id. at 2.

[23] In a 2019 interview with WHYY-FM radio station, a representative of the Homeowners Association of Philadelphia expressed support for requiring landlords to supply air conditioning. See Jake Blumgart, Should Landlords be Required to Provide Air Conditioning?, WHYY (July 19, 2019), []. See also Carlson, supra note 5, at 209-10.

[24] Pennsylvania Department of Human Services, Heating Assistance / LIHEAP, [] (last visited Apr. 25, 2022).

[25] Carlson, supra note 5, at 210. Although PA LIHEAP usually assists with heating bills only, in the fall of 2021 PA LIHEAP did offer some funding to prevent utility shutoffs generally. See PULP (NON) FICTION ISSUE 6, PENNSYLVANIA UTILITY LAW PROJECT (Sept. 2021), [].

[26] See COMMONWEALTH OF PENNSYLVANIA, Low-Income Home Energy Assistance Program Fiscal Year 2022 Proposed State Plan i (2021), [].


[28] 24 C.F.R. § 965.505(e). For residents using vouchers, HUD requires PHA’s to provide utility allowance for air conditioning costs if the majority of housing units in the market provide central air or if there is wiring appropriate for installing air-conditioning. 24 CFR § 982.517(b)(2)(ii).

[29] See, e.g., Blumgart, supra note 23.

[30] Amone v. Aveiro, 226 F.R.D. 677, 688, 680 (D. Haw. 2005). The lead plaintiff required use of an oxygen machine, nebulizer, and air conditioner, and because of a low utility allowance was using half of her income for rent. Id. at 680.

[31] Id. at 680.

[32] Amone v. Aveiro, Civ. No. 04-00508 ACK/BMK, WL 2479291, at *29 n.121 (D. Haw. Aug. 27, 2007); Giles v. Hous. Auth. Of Frankfort, No. 89-107 (E.D. Ky. May 3, 1990), 24 CLEARINGHOUSE REV. 257 (No. 45,074, July 1990).

[33] Pearsall, supra note 2, at 90-91.

[34] Philadelphia Parks and Recreation, Street Trees, [] (last visited Apr. 25, 2022).


[36] Street Trees, supra note 34.

[37] Susana María Aguilera, Prioritizing Tree Planting in Shade-Deprived Urban Areas as a Response to Climate Change, 27 HASTINGS ENV’T L.J. 101, 108 (2021).

[38] Sam Bloch, Shade, PLACES (Apr. 2019), [] (“Ted Watkins, a Ford plant employee, was early to recognize the need for shade in South Los Angeles. After the Watts riots, he took out a loan from the United Auto Workers to buy empty lots and build parks. He founded the Watts Labor Community Action Committee, which became one of the area’s largest private landowners, controlling many low-income apartment complexes. In the 1960s and ’70s, the organization hired neighborhood kids, including Watkins’s son Tim, to plant street trees as part of a city contract. Many of those trees are still standing, like the “monstrous” windbreaks Tim remembers planting on Pacific Coast Highway, as well as thick canopies of ficus in Hollywood and parkway groves in the San Fernando Valley.”).

[39] Id. (“Aaron Thomas, the arborist, lamented that the city won’t permit the planting of large trees in parkways less than five feet in width, because the roots could rip up sidewalks or destroy underground utilities. That effectively zones shade out of many poor neighborhoods….Thomas and I walked past a stretch of auto body shops and parking lots, on sidewalks that were only three feet wide. To plant a shade tree here, he explained, the street would have to be extensively reengineered and the sidewalk expanded. I pointed to an empty well across the street. Too close to a driveway, he said, and anyway, it would have to be a small, shrubby species, because of the criss-crossing wires overhead. ‘The rule is, if the branches are within 30 feet of the powerlines, then the DWP is allowed to come in and prune ’em back.’ ‘That’s, like, every street tree,’ I said. ‘Often. And you’ve got a water main right there. So the roots of the tree will always be in conflict with it.’”).

[40] Pearsall, supra note 2, at 90.

[41] Id. at 91.

[42] Id.

[43] The Public Interest Law Center, Garden Justice Legal Initiative, [] (last accessed Apr. 25, 2022). The Garden Justice Legal Initiative provides legal assistance and toolkits related to adverse possession claims and other legal routes to access and strategically target land. For example, a community group may not be able to find the owner of a vacant lot they hope to work on, or may need legal representation in order to file for land conservatorship or raise an estate.

[44] Aguilera, supra note 37, at 118.

[45] Sterling Johnson & Kimberley Thomas, Green Gentrification in South Philly, EDGE EFFECTS (Nov. 4, 2021), [].

[46] Id.