Los Angeles tests pavement paint that fights climate change

The City of Los Angeles is testing a paint that might reduce the urban heat island effect.

Normal black asphalt absorbs around 80 to 90 percent of sunlight. This is a big concern in areas like Los Angeles that receive a lot of sunlight. The asphalt absorbs the heat and reflects it back, leading to urban temperature increases. The high temperatures, in turn, lead to more need for energy-sucking air conditioning. Methods for reducing the urban heat island (UHI) include planting trees, using asphalt made from cigarette butts, and using evaporation to cool buildings. Now, Los Angeles is set to become the first city to try a new method – cool asphalt paint.

Demonstrations have shown that painting city streets with a hard-wearing grey asphalt paint can reduce temperatures at street level by as much as 10 degrees Fahrenheit. The grey CoolSeal paint, produced by California-based GuardTop, works by reflecting the sunlight, lowering ground temperatures. Los Angeles is the first city to test the treatment on sections of public road, after initial trials on parking lots proved successful. The test will also measure how quickly the grey coating turns black from traffic, and how Angelenos react to the new street color. Residents living in the neighborhood being used for the tests reported that they could feel a difference in temperatures after just a few weeks.

Climate models suggest that by mid-century, parts of L.A. could witness up to three times as many days with temperatures of more than 95 degrees. While the grey pavement won’t change that, it could help to make the city more livable, although some suggest that the manufacture of the paint could in and of itself add to greenhouse gas emissions. For now, city officials hope their experiment inspires other cities to experiment with ways to reduce urban heat, and encourage manufacturers to create new products. What other creative solutions might help cities cope with increasing heat from climate change?