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Autumn, 2025

All flat roofs along Mass Ave painted white to decrease urban heat island effect.

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One of the most important consequences of climate change is global warming. Due to human activities, (in other words, the burning of fossil fuels – coal, oil, gas), the Earth has been slowly creeping up in temperature with increasing industrialization. Since the pre-industrial period (between 1850 and 1900), countries and individual states/cities are hitting record high numbers everyday as the temperatures increase and it is going to get worse. For example, the nearby City of Cambridge’s 2015 Climate Change Vulnerability Assessment estimated that by 2030, “the number of summer days above 90 degrees could triple.”  Not only is extreme heat like this uncomfortable to many, but it is considered a more dangerous threat to human health than flooding. So, what can we do to help?


The typical answer to this question usually falls along the following suggestions: Using metal straws in place of plastic straws, taking public transportation in lieu of emitting gas into the atmosphere from a car, setting up a compost bin to recycle organic matter rather than choosing the easy option of tossing the garbage into a trash bin, and such. However, these tasks may seem inconvenient or even ineffective to some and therefore they might choose to opt out of implementing these solutions into their everyday routines. So, are there any other ways to help without putting in extra work, everyday? In fact, there are.


Our roads and parking lots, made of concrete and black asphalt, significantly contribute to our rising temperatures; in cities and towns, paved surfaces dominate the landscape, causing what is referred to as “urban heat islands.” The dark black colors absorb up to 90% of the sun’s radiation and warm up the surrounding air. Roads make up a large percentage of US land, with “approximately 18 billion tons of asphalt pavement on America's roads” (National Asphalt Pavement Association). Zooming out and looking at our Earth from a bird’s-eye view, you can immediately see that populated areas of land are filled with long black lines; as if these areas were decorated with strips of black carpet, placed neatly on the floor to signify a walking or driving area. However, if you were to zoom into an individual street, not only would you see the black strip of road, but on either side will be something else with this familiar dark color– roofs.


A large majority of flat roofs are black and made from a material called asphalt roll. Not only are roads being created with this highly sun-absorbing material, but most flat roofs on commercial and apartment buildings are also topped off with this same heat-absorbing color, in direct view of the sun. With this in mind, it is simple to understand why so much heat is trapped, and therefore, why our temperatures are increasing fastest in cities. In addition, more energy is required for air-conditioning to cool the interior of these buildings, increasing our carbon footprint.


White roofs have become increasingly popular and have started to be recommended or even required in zoning regulations around the U.S. as a way of addressing local heat problems. This article from 2014 clearly breaks down the negative effects of asphalt/black roofs and explains how white roofs can reduce this. Requiring white roofs as a way to reflect heat from the sun is a solution that will prevent black/asphalt roofs from absorbing heat and increasing Arlington's daily temperatures.




Regulations should be established so that all new buildings and homes built throughout Arlington are automatically constructed with flat white roofs or light-colored shingles. As for the structures that are already standing, our hopes would be to get grant funding in order to start painting these roofs white, starting with the Mass Ave corridor.


In the future, our goal is to go even further – to convert from white roofs to green roofs, meaning roofs covered in plants and vegetation. There is an ongoing debate regarding the effectiveness of white roofs; green roofs have additional advantages. As new buildings are being built, they can be engineered in a way to safely carry the weight of soil and plants. Green roofs are not just beneficial for regulating sun-absorption, but for, “reducing and filtering stormwater runoff; absorbing pollutants and carbon dioxide; providing natural habitat; and in the case of intensive green roofs, serving as recreational green space” (Using Cool Roofs to Reduce Heat Islands). (More information on green roofs can be found here.)


Steps need to be taken to save our slowly dying planet. Without immediate change, the temperatures will continue to climb, storms will become increasingly dangerous and sea levels will rise and produce massive floods. No matter how much effort individuals can put into this fight, every resident should be taking action. As listed above, simple solutions have been created. It is important to evaluate the time that you have and set goals for yourself as to what you will do, daily, to combat climate change. White roofs are a wonderful way to get involved with minimum effort as it does not require daily work. After all, you only have to paint your roof once! More information on white roof maintenance can be found here.




City of Cambridge, Climate Change Vulnerability Assessment & Neighborhood Plans


NAPA (National Asphalt Pavement Association), Fast Facts



Nation Swell, The Rooftop Decoration That Could Cut Your Energy Costs


EPA, Using Cool Roofs to Reduce Heat Islands


Green Roofers, Advantages and Disadvantages of Green Roofs


Facility Executive, Keep Cool, With Proper Cool Roof Maintenance 


City of Cambridge, How to Stay Cool During Extreme Heat


AGU/Thriving Earth Exchange, Developing a Methodology for Measuring Changes in Albedo to Reduce Urban Heat Island Effect

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