The Vicious Cycle of Urban Heat Islands
This summer it feels as though every other week Charlottesville and Richmond have been under a heat advisory. Similar to last summer, and the one before, heat waves have become increasingly common. The U.S. and many other parts of the world are facing more extreme temperatures than ever recorded. Heat-related illnesses and death have also been on the rise over the past few decades, often exacerbated by the heat island effect in urban areas [5].
The explanation for this dire weather situation may lie under our feet. When we walk from the car to the grocery store or among downtown skyscrapers, these hotspots of concrete, asphalt, and glaring windows can create what are known as urban heat islands.
What are Urban Heat Islands?
The Environmental Protection Agency defines urban heat islands as “areas that experience higher temperatures than outlying areas” [4]. Many factors and materials create urban heat islands. The most common is man-made infrastructure. Building materials, such as steel and concrete, absorb and radiate heat during high temperatures, making hot days hotter. Urban heat islands are also created by a lack of natural landscapes. Trees, ponds, rivers, and grass reflect heat and provide shade, decreasing average temperatures. Other factors that cause heat islands are urban design and human activity. Poorly planned urban design, especially narrow streets between high-rise buildings can create heat canyons due to lack of windflow. Lastly, cars, air conditioners, and industrial facilities emit heat that can make heat islands worse. On average, urban heat islands can be 1-10°F warmer than outlying areas [4].
When many think of urban areas, they think of New York City, Los Angeles, and Chicago. However, vast asphalt parking lots, dense mid-rise buildings, and lack of natural landscapes are an integral part of American towns and suburbs. These urban heat islands aren’t just infiltrating large cities, but also Charlottesville and Richmond alike.
Charlottesville
In March 2022 the City of Charlottesville conducted research on the area’s urban heat island effect and completed an assessment of tree canopy coverage. The study separated the city into the 19 Planning Neighborhoods of Charlottesville and assessed their heat index and tree cover. The image on the left illustrates that the neighborhoods 10th & Page, Starr Hill, Belmont, the Meadows, and North Downtown have between 30% to less than 20% tree canopy coverage. On the right, the Heat Island Severity Map shows that similar areas, specifically the Downtown Mall in North Downtown and Charlottesville High School in the Meadows were heat spots that, on average, were 1.25°F higher in temperature [2].
Image 1 (left) depicts the percentage of Urban Tree Canopy allocated amongst the 19 Neighborhoods of Charlottesville. Areas in red have lower tree canopy percentages. Image 2 (right) depicts the Heat Island Severity across the City of Charlottesville. The two maps are meant to show the inverse relationship between urban tree canopy coverage and heat island severity.
Areas, specifically 10th & Page and North Downtown are well-known for wider roads and higher rates of car and train traffic. Additionally, The red sections of the Heat Island Severity Map are areas with large parking lots, such as Barracks Road Shopping Center and Charlottesville High School [2].
It is also important to note that 10th & Page is one of, if not the oldest predominantly Black neighborhoods in Charlottesville. This is because the neighborhood is a product of the expansion of the UVA Hospital in the 1950s. At the time, dozens of African Americans homes in Fifeville were bulldozed, and, due to redlining, were only able to rent in the neighborhoods 10th & Page and Starr Hill [8]. They were only able to rent at the time because African Americans were considered too ‘hazardous’ to process private and federal loans for house ownership [9]. Because they were unable to own housing, they were unable to plant trees and landlords were unwilling to invest in green infrastructure, inevitably creating urban heat islands. Although created in the 1960s, these urban heat islands have persisted into today.
Richmond
Image 3: The graph depicts the correlation between impervious surfaces, land surface temperatures, and HOLC Neighborhood Grades. This graph was designed and created by Dr. Jeremy Hoffman.
Richmond faces a similar issue but on a larger, more historic scale. Dr. Jeremy Hoffman conducted a study on the correlation between urban heat islands and the grade of neighborhoods based on the Home Owners Loan Corporation (HOLC) from 1933 [1]. Staggering results concluded that historically minority neighborhoods faced higher temperatures due to less tree canopy cover and greater radiant infrastructure compared to historically white, wealthy neighborhoods. Hoffman argues that because the HOLC graded (A-D) historically minority neighborhoods as D class, people trying to live in those areas were less likely to receive loans for mortgages, causing property values to fall. These lower property values caused less investment in green infrastructure, creating the heat island effect we see today [3]. In many of these areas, people of color continue to live within these neighborhoods, putting them at a greater risk of heat-related illnesses.
A Vicious Cycle
By not combating the urban heat island effect in our cities and the continuous expansion of urban sprawl, temperatures and heat-related illnesses will continue to rise [7]. More impervious infrastructure that is dependent on cars, such as freeways and parking garages, will continue to amass heat-related consequences. People living within urban heat islands will continue to be more likely to experience an increased electricity use to stay cool. This increase in energy use will perpetuate the ongoing strain on the Earth’s natural resources, generate more carbon emissions from electrical power plants, and eventually worsen the greenhouse effect. The increased demand for air conditioning will cause electricity bills to rise, hurting lower-income people who are already more susceptible to living in urban heat islands that lack green infrastructure investments.
No individual is to blame for this vicious cycle of increasing temperatures and energy consumption, but rather it is a symptom of a historic issue created from decades of disregarding lower income and predominantly Black communities. Urban heat islands are now within the hands of our communities and can be resolved through collaborative group efforts.
How do we Combat the Issue?
Local communities, non-profit organizations, and other climate justice organizations within Charlottesville and Richmond are already combating the urban heat island effect:
Groundwork RVA: Groundwork RVA is dedicated to educating local youth on the importance of green spaces in urban communities through their Green Team and Green Workforce programs. Groundwork RVA owns the Bellemeade Community Bike Shop that teaches students about bike safety and local trails to commute to school.
Southside ReLeaf: Southside ReLeaf concentrates on planting trees in the Southside of Richmond where the majority of urban heat islands exist. Through volunteer activities and policy advocacy, Southside ReLeaf is working to enhance and expand Richmond’s green infrastructure in areas that need it the most.
C3 Energy Efficiency Grants: The Community Climate Collaborative has extended their deadline to July 31st for $2,000 Energy Efficiency Grants. Small businesses are encouraged to apply to receive a free energy inspection.
Local cooling centers: Charlottesville and Richmond offer free cooling centers for people in need. For a list of Charlottesville locations, click here. For a list of Richmond locations, click here.
Climate Justice Research: This summer, C3 kicked off their RVA energy burden study, which will research and map energy burden across Richmond. The study aims to craft policy and advocacy recommendations that address energy affordability and the impacts of climate change [11].
Sources:
[1] Hoffman, Jeremy S. “Throwing Shade in RVA.” Available at: https://jeremyscotthoffman.com/throwing-shade
[2] “Urban Tree Canopy Assessment” March 2020. Available at: https://www.charlottesville.gov/ArchiveCenter/ViewFile/Item/221
[3] Saverino, Kelly, et. al. “Thermal Inequity in Richmond, VA: The Effect of an Unjust Evolution of the Urban Landscape on Urban Heat Islands.” Feb. 2021. Available at:
https://www.mdpi.com/2071-1050/13/3/1511
[4] “Learn about Heat Islands.” EPA. Available at:
https://www.epa.gov/heatislands/learn-about-heat-islands
[5] “Climate Change Indicators: Heat-Related Deaths.” EPA. Available at:
https://www.epa.gov/climate-indicators/climate-change-indicators-heat-related-deaths
[6] Groundwork RVA available at: https://www.groundworkrva.org/
[7] Rafferty, John. “The Problem of Urban Sprawl.” Britannica. Available at: https://www.britannica.com/explore/savingearth/urban-sprawl
[8] Yager, Jordy. “A new page: Longtime 10th and Page residents are seeing a shift in the neighborhood.” C-VILLE Weekly, Dec. 2017. Available at:
https://www.c-ville.com/new-page-longtime-10th-page-residents-seeing-shift-neighborhood/
[9] Entzminger, Brielle. “Uncovered: How racist redlining shaped our urban forest.” C-VILLE Weekly, Oct. 2020. Available at: https://www.c-ville.com/uncovered-how-racist-redlining-shaped-our-urban-forest
[10] Southside ReLEAF. Available at: https://www.southsidereleaf.org/our-work
[11] Düster, Maria. Climate Justice Research, July 19, 2024.