Why Wisconsin’s dark skies are disappearing (& how to get them back)

Newport State Park, DarkSky International

By Christina Lorey

February 25, 2025

The lightbulb is arguably the best invention since before sliced bread. But, there’s a tradeoff.

“I think the brightening of the night sky over our cities, the places we live, actually represents one of the most profound transformations of the natural environment,” Ruskin Hartley, executive director of DarkSky International, explained. “We’ve introduced lights into the dark, natural environment in a way that it has never experienced before in the more than 4 billion years of the Earth’s history.”

Light pollution is a stress on the national environment, just like habitat loss and climate change, and it’s causing many problems. One impact is on our ability (or inability) to see the stars. Another is on migration: bright city lights draw birds off their path, where they collide with buildings and die. It’s even affecting life below the waves, as certain fish (like clownfish) can’t reproduce under artificial light levels.

The level of light pollution really depends on where you live. NASA has a free, interactive light pollution map where you can enter your zip code and find out how polluted your city is.

🌃 TRY IT: Interactive Light Pollution Map

Wisconsin’s most light-polluted cities are the big ones–Milwaukee (and nearly all its suburbs), Madison, Green Bay, Appleton, Wausau, and Eau Claire.

So, what’s the solution?

Reducing light waste–and it’s far easier than you might expect. “Do we really need to have our porchlight on at 2 a.m. when there’s no one around, or can we put it on a motion sensor, so when someone returns home late, it comes on and turns off five minutes later?” Hartley said. “It’s thinking about darkness as a precious resource.

DarkSky International released a list (linked here) of 5 ways you can reduce your light waste. Suggestions include using warmer sources of light instead of white lights and directing light, so it only falls where it’s needed.

Author

Christina Lorey

Christina Lorey is an Edward R. Murrow Award-winning journalist and former UpNorthNews newsletter editor. She previously worked as a producer, reporter, and TV anchor for stations in Madison and Moline. When she’s not writing or asking questions, Christina volunteers with Girls on the Run, the Pancreatic Cancer Action Network, and several mental health organizations.

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CATEGORIES: NATURE

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