In roofs, that is–at least in tropical and temperate climates. The all purpose little black dress and the energy saving white roof won’t go out of style. But first, we have to get those white roofs in style. Here’s a way to start: flat roofs can be painted with a white elastomeric coating that is rated to reflect back 88 percent of the sun’s heat; a black roof might absorb as much as 85 percent of the heat. And because so many cities are full of flat black roofs, they are subject to the Heat Island Effect in summers. The elastomeric coating can save people 20-50 percent on their cooling bills, and that makes doing it tempting, especially since the coating also protects flat roofs from those little hairline cracks that turn into leaks. The elastomere can add ten years to the life of a flat roof–or, if it’s reapplied every 7-10 years it can make a roof last indefinitely.

Admittedly, a white roof wouldn’t do people in Anchorage much good; it would just add to their heating bills–same in Minneapolis or Detroit. But in, say, Chicago or New York or anywhere south of that, it would be worth having. And white roofs do more than just save homeowners money; they could be crucial to slowing global warming. Nobel laureate and Energy Secretary, Steven Chu, is advocating for white roofs on all buildings and for light colored pavement, not only in our country but worldwide.

“Make it white,” he advised a television audience on Comedy Central’s “Daily Show” last week.

The scientist Mr. Chu calls his hero, Art Rosenfeld, a member of the California Energy Commission who has been campaigning for cool roofs since the 1980s, argues that turning all of the world’s roofs “light” over the next 20 years could save the equivalent of 24 billion metric tons in carbon dioxide emissions.

“That is what the whole world emitted last year,” Mr. Rosenfeld said. “So, in a sense, it’s like turning off the world for a year.”

Trust California to come up with that idea before the Midwest does. When the end of the world comes, I want to be in Missouri, because we’re always ten years behind the times. No wait. We’re behind the times on white roofs but ahead of the times on global warming. All the more reason that one former conservation organizer for the Sierra Club, Jill Miller, started a business to try to bring white roofs to St. Louis. When she was still working for the Sierra Club, she looked around at the sea of flat dark roofs in St. Louis: “I kept thinking that somebody oughta do something about this and finally decided that perhaps I was that person.”  Her company, White Caps, Green Collars, puts that white elastomeric coating on roofs. Depending on the size of the residential roof, it would cost somewhere in the neighborhood of 1000-1500 dollars.

Of course, homeowners worldwide aren’t going to rush out this year to make the change. Converting the world to white roofs will mostly happen gradually, as residents find it necessary to put new roofs on their homes. Miller explains the huge environmental benefits, both locally and worldwide, that will accrue as that occurs. By reducing the heat a city emits, we reduce smog and therefore asthma problems. More importantly, lowering our electric use lowers the carbon we put into the atmosphere and offsets the damage done by the loss of reflectivity from melting polar ice caps. And we’re creating green jobs in the process.