If you’ve been outside recently, you probably realize that this summer is hot. With the latest heat wave now spreading across the country, it’s worth pointing out that many Americans are unknowingly contributing to the soaring temperatures. How? Millions of rooftops in America are made of black tar; and they absorb and trap an enormous amount of heat during the summer months. It’s also worth pointing out that there’s an easy fix to the black roofs problem that people of all political stripes can get behind: paint the black roofs white.

Painting black tar roofs with a white, solar-reflective coating is a low cost, quick and tangible way to reduce the risk of power grid ‘brown-outs’, save millions of dollars in energy costs, and curb climate change. The statistics are as simple as they are staggering: A roof covered with solar-reflective white paint reflects up to 90% of sunlight as opposed to the 20% reflected by a traditional black roof. On a 90°F day, a black roof can be up to 180°F. That heat has a major impact on interior building temperature, potentially heating your room to between 115 – 125°F. A white roof stays a cool 100°F. Plus the inside of the building stays cooler than the air outdoors, around 80°F in this example, reducing cooling costs.

White roofs also reduce the “urban heat island” effect in which temperatures rise in dense urban areas because of the proliferation of heat-radiating, black tar surfaces. For example, the Urban Heat Island effect causes New York City to be about 5 degrees warmer than surrounding suburbs and accounts for 5 to 10 percent of summer electricity use.

In New York City alone, 12% of all surfaces are rooftops. It’s estimated that implementing a white roof program in 11 metropolitan cities could save the United States 7 gigawatts in energy usage. That’s the equivalent of turning off 14 power plants, and a cost savings of $750 million per year.

Recently, former President Bill Clinton wrote in Newsweek, “Every black roof in New York should be white; every roof in Chicago should be white; every roof in Little Rock should be white. Every flat tar-surface roof anywhere! In most of these places you could recover the cost of the paint and the labor in a week.” The former president regularly touts the white roofs as one of those win-win scenarios that could also help create jobs and stimulate the economy.

The folks at White Roof Project agree. Last year, a progressive group of young people got together to found the project and get it going at the grassroots level. When 150 volunteers showed up to coat the historic Bowery Mission in New York City (our first project) it was a watershed moment. Volunteers saw that all it takes is a paint roller, some solar-reflective white coating and a little hard work to start curbing climate change. Since then we’ve been educating and activating our neighbors around the white roof movement that Bill Clinton has called on someone to build.

This year, White Roof Project will triple the amount of roofing it coated last year and is also launching a campaign to educate more homeowners and organizations about the benefits of white rooftops.

If we were to coat 5 percent of rooftops per year worldwide, we would be finished by 2030. This would save the U.S. 24 billion metric tons in CO2. That happens to be exactly how the world as a whole emitted in 2010. So, in essence, this would be like turning the world off for an entire year — while also saving some money on the energy bills while doing it.

A White Roof Project is a common sense concept that’s easy to implement and creates tangible change for individuals, our communities, and even globally. As we head towards the dog days of August, there’s no better time to grab a brush — except it’s probably a good idea to wait for a cooler day.