Blog Post 2
NYC Hot Spots: Understanding the Urban Heat Island Effect and Its Latest Victims
Heatwave GIF by Ardodue [Digital Image] (2023) https://tenor.com/view/heat-wave-heat-gif-27573505
Over the years, NYC’s summers have become unbearably hot. The public has classified this increase in heat as an effect of global warming, although it’s a contributory factor; it’s truly a direct result of urban development (Maldonado, 2023). As the US’s largest city, NYC is overpopulated, and to compensate, the city has built an immense amount of tall and large buildings intended to hold such a large quantity of people. These buildings are meant to provide shelter, workspaces, or places merely for entertainment and leisure. Unfortunately, these buildings are accompanied by prominent drawbacks, as they are made from heat-absorbing materials, namely concrete, asphalt, and brick, and end up being colors such as dark gray, brown, and black, which can’t efficiently reflect light. It’s not just buildings but also the roads, sidewalks, and parking lots, as these aspects of city infrastructure are also typically made from materials known to absorb heat. Consequently, the dense infrastructure of neighborhoods like Fordham, Jamaica, Harlem, and Brownsville has made them the city’s biggest hot spots, and not in a good way.
This excessive heat is referred to as the urban heat island effect, which the U.S. Environmental Protection Agency professionally defines as “a measurable increase in ambient urban air temperatures resulting primarily from the replacement of vegetation with buildings, roads, and other heat-absorbing infrastructure. The heat island effect can result in significant temperature differences between rural and urban areas” (System of Registries | US EPA, n.d.). Rural areas tend to be more open and spacious, so there isn’t much for the heat to be trapped in, which is what creates the drastic difference in temperatures between urban and rural areas. As shown in the picture above, urban areas densely construct buildings and roads from materials such as concrete, asphalt, and brick, which tend to absorb heat and increase the intensity of the urban heat effect. When the buildings are heat magnets and so closely placed, it allows for the heat concentration of that particular area to increase by large amounts.
Color is also a significant contributing factor. Light colors, particularly white, silver, and pastels, effectively reflect sunlight, while dark colors like black, dark gray, and brown do the opposite and absorb sunlight. Relating this to the urban heat effect, the majority of buildings, roads, and sidewalks tend to be dark colors, which induce heat absorption (Admin, 2018). Residents seeking relief from the heat resort to air conditioning units, further contributing to heat, leaving cities trapped in an endless cycle where heat is constantly being produced and trapped. Not only is human activity and construction material intensifying heat, but the color as well. Color will not just make neighborhoods look more lively but also cool them down, making them more livable.
One of the most prominent victims of the urban heat effect is New York City. The city compacts tall buildings close together, simultaneously preventing wind from flowing into the area and not allowing heat out, which is referred to as urban heat canopy (Mahoney & Mahoney, 2021). Heat continues to build up with no way out, and as a result, residents are trapped in this heat and experience miserable temperatures. The biggest cause of the urban heat effect is the lack of green spaces in the city, and the ones that do exist tend to get torn down and be replaced by parking lots and skyscrapers. Greenery cools down the areas by absorbing less heat and actually releasing water vapor into the air through transpiration (The Central Park Conservancy, 2024).
Neighborhoods like Fordham, Jamaica, Harlem, and Brownsville are more vulnerable to the urban heat island effect as they lack green spaces and are densely constructed. Studies from the Bureau of Environmental Surveillance and Policy has revealed the amount of green space in Fordham is 10.6 %, Brownsville 25.7%, Jamaica 14.7% and Harlem (South) 19.6% (Interactive Heat Vulnerability Index. – Environment & Health Data Portal, n.d.). These are some of NYC’s most densely populated neighborhoods so this amount of green space isn’t proportionate to the population or the amount of buildings, making it ineffective at cooling down the area. These neighborhoods are largely made up of tall residential buildings and parking lots and unfortunately tend to be overlooked as abandoned buildings and lots pile up that just sit there absorbing heat.
Data has shown that the block of West 94th Street near Central Park was 84 degrees, but across town, at a treeless lot for sanitation trucks on First Avenue in East Harlem, it was 115 degrees (Leland, 2021). These areas can be changed to incorporate greenery or transformed completely but it seems like no one will take action, creating a situation where the heat becomes unbearable
It may not be so convenient to change the construction materials or build more parks, but something that can easily be done is planting more trees to provide shade for the streets and creating green spaces on the tops of the buildings. If you want to take it a step further, reflective roofing systems. Some have already started to implement this, but it won’t be as effective if everyone doesn’t participate. Together we can make a difference, creating a greener and cooler NYC.
References
Admin. (2018, August 23). Rising Temperatures and The Urban Heat Island: What it Means NYC – New York League of Conservation Voters. New York League of Conservation Voters. https://nylcv.org/news/rising-temperatures-urban-heat-island-means-nyc/
Interactive heat vulnerability index. – Environment & Health Data Portal. (n.d.). Environment & Health Data Portal. https://a816-dohbesp.nyc.gov/IndicatorPublic/data-features/hvi/
Joseph, J. (2025, April 18). Dense layout of buildings at E 14th St and Broadway [Photograph]
Leland, J. (2021, August 20). Why an East Harlem Street is 31 degrees hotter than Central Park West. The New York Times. https://www.nytimes.com/2021/08/20/nyregion/climate-inequality-nyc.html
Mahoney, A., & Mahoney, A. (2021, August 13). Tall buildings: Good for the housing crisis, bad for the climate crisis. Grist. https://grist.org/buildings/ipcc-urban-heat-islands-tall-buildings-housing-crisis/
Maldonado, S. (2023, July 26). How much hotter is NYC’s heat island effect making your neighborhood? THE CITY – NYC News. https://www.thecity.nyc/2023/07/26/heat-island-hot-map-temperature/.
System of Registries | US EPA. (n.d.). https://sor.epa.gov/sor_internet/registry/termreg/searchandretrieve/glossariesandkeywordlists/
The Central Park Conservancy. (2024, May 29). A need for trees: How Central Park cools the (Urban heat) island of Manhattan. Central Park Conservancy. https://www.centralparknyc.org/articles/how-central-park-cools-the-heat-island.
