Douglas Stotz

Tucson, Arizona changed the color of 20,000 streetlights, cut light pollution by 7%, prevented countless wildlife deaths, and saved taxpayers a boatload of money. Most cities retrofitting streetlights to LED chose cool-white bulbs in the 4,000K range because they're bright and cheap. Cool-white light scatters upward and sideways at higher rates than the old sodium lamps, which is why light pollution has actually increased in many cities that switched to LED. Hundreds of millions of migrating songbirds navigate by stars and get pulled off course by that scatter every year, many of them fatally. Tucson chose warm-white 3,000K LEDs instead, added full shielding so the light points down rather than up or sideways, and programmed adaptive dimming: 90% brightness from sunset to midnight, 60% after that until dawn. It was a win for wildlife and taxpayers: the whole thing costs less to run than what it replaced. Philadelphia, LA, and Phoenix have all run LED retrofits that made skyglow worse. The technology to do it right exists and isn't expensive. It's a procurement decision, which means it's a political one. And political decisions are ones you can influence. Your city council chose your streetlights. Most of them have never been asked about color temperature, shielding, or dimming schedules, not because those things don't matter, but because most people don't know to ask. The night sky is habitat. The darkness migrating birds need to navigate is habitat. We've been treating it as a waste product of lighting decisions made by people who weren't thinking about birds. Ask your council what color temperature your streetlights are. Most of them won't know the answer.