The Los Angeles City Council has voted unanimously to require “cool roofs” for all new and refurbished homes, becoming the first major U.S. city to do so. “Cool roofs” incorporate light- and heat-reflecting building materials, which can lower the surface temperature of the roof by up to 50 degrees F on a hot day, according to Climate Resolve, the local organization that pushed for the ordinance. Such roofs do not necessarily need to be white, the Global Cool Cities Alliance says; they can also be shades of gray, or even red. Research suggests that by mid-century temperatures in Los Angeles will increase by 3.7 to 5.4 degrees F, with the number of days above 95 degrees F tripling in the city’s downtown. “The changes our region will face are significant, and we will have to adapt,” said UCLA scientist Alex Hall, who led the research. The mandate will not cost homeowners additional money because of expanded incentives.