Between 30 and 50 percent of outdoor lighting is wasted, with $1 billion worth of stray lumens released into the air each year. (Google “NASA Earth nightlights” if you don’t believe it.) Not only does overlighting obscure the night sky, confuse birds, and add CO2 to the atmosphere, but recent research has found that it also screws up our circadian rhythms. And until recently, little towns like Davis, California, and Flagstaff, Arizona, were the few bright spots in dark-sky preservation.
There’s reason to think the big boys will be headed that way soon, though. It’s estimated that in the next few years, LEDs will be 40 percent more efficient than the 37 million high-pressure sodium lights currently lining our streets, a savings that will spur a switch. Since LEDs shoot straight, putting light where they’re pointed and not up into the stratosphere, they’re a big part of the dark-sky equation. More important, in June the Tucson, Arizona–based International Dark-Sky Association (IDA) released the Model Lighting Ordinance for urban areas. The plan recommends cities set up lighting zones. Think of it as a municipal cap-and-trade system: in New York City, Times Square could keep its brights burning while downtown Brooklyn dims its parking lots, hoods streetlights, and darkens office buildings. The plan hasn’t been in circulation long enough for anyone to vote it into law, but IDA director Bob Parks is confident we’ll see several metropolises going dark soon. “For the past year, I’ve had cities calling me every few weeks asking if this was ready,” he says. “It’s the tool they’ve all been waiting for.”