The adverse effects of human-caused climate change have really started taking a toll on communities across the globe; 2024 was the hottest year on record, and several regions faced more frequent and deadly flash floods, wildfires, and storms than ever before. In order to combat these rising temperatures, some cities have resorted to painting black asphalt roadways with lighter colored paint, and we might want to start doing the same with our cars. A new study found that dark-colored cars parked in urban areas can raise the air temperature around them by about 3.5°F.
Urban areas are already known to be hotter than other less-developed areas because of black asphalt, dark buildings, and other sources, but until now no one suspected the impact the humble parked car could have on urban temperatures. If you’ve ever plopped your butt down on a black leather seat that’s been sitting in the sun or scorched your fingers on a black steering wheel, you know how much heat dark-colored surfaces can retain. As a new study coming out of Lisbon, Portugal finds, the same goes for the impact that dark cars have on the air.
It’s due to physics
The exterior of most vehicles on the road is primarily made up of thin metal panels, which heat up faster than other dark surfaces found in urban areas like asphalt, and radiates that heat into the surrounding air. In this study, geographer Márcia Matias parked a black car and a white car in the sun for several hours. When she measured the temperature of the air around each car, she found that the black car was radiating as much as 3.8°C more than the asphalt it was parked on. ZME Science said, “the white car had a much smaller effect—sometimes even producing lower local air temperatures than the street itself.”
Take the car loving city of Los Angeles, for example. It has about 200 square miles of parking spaces according to Bloomberg, which is an awful lot of space for cars to inhabit. Considering that Los Angeles is one of the sunniest places in the country, experiencing an average of about 275 days of sunshine per year, that all adds up to a lot of potentially air-warming cars.
What does it mean?
While this doesn’t mean there will be a ban on dark-colored cars, it’s a useful data point that can be leveraged to help relieve some of the “urban heat island” effects. In an interview with NPR, Matias said, “fleets of municipal vehicles, like buses and police cars, would be a good start and could be a small step in making the sweltering summer heat a little more bearable.” She also said that governments could encourage manufacturers to use reflective coatings, or get people to buy brighter cars.
The study notes that the data is somewhat limited, stemming from data collected at a specific time, but Matias is confident that the phenomenon impacts urban air temperatures. It could be prudent to start with commercial vehicles and incentivize companies for repainting their vehicles. There’s no mention of how panoramic glass roofs that are common in new cars radiate heat, but maybe manufacturers could offer more cars with two-tone paint schemes with contrasting white roofs, or offer more enticing, brighter paint options.
