‘I want people to care about the night’: Advocates are working to fix light pollution in Chicago area

When you flip on your bright porch lights each night, you could be doing more than muddying your view of the Milky Way: Unnecessary light disrupts wildlife, affects human health and contributes to climate change, advocates say.

The Chicago area is a particularly shiny example of light pollution, with light emissions several times higher than what many scientists say are needed.

For instance, consider Cook County and the Berlin metro area. Though similarly sized and populated, we emit more than seven times the amount of light as the German city.

“It’s a perfect example of, ‘Wait a minute, it's not like you have to do it this way,’” said Ken Walczak, a senior manager at the Adler Planetarium, adding that our streetlights, residential lights and even interior lights are commonly several times brighter than standard recommendations.

With human biology trained to a day-to-night cycle over four and a half billion years of evolution, the relatively recent proliferation of electric light has already begun altering that cycle, Walczak said.

According to research out of the UTHealth Houston School of Public Health, the connection between poor health and bright artificial light is well-established. The light throws a wrench in our biological clocks, creating long-term health consequences like cognitive decline, heart disease and cancer.

The effect on the natural world is just as significant.

“Seventy percent of all mammals are nocturnal,” Walczak said. “If we've extinguished the night, think about the ramifications that has for so many species and so many ecosystems.”

Naturalist Valerie Blaine, who is retired from serving as the nature program manager for the Kane County Forest Preserve, said she always thought light pollution was something only astronomy buffs cared about — until she realized how diverse and far-reaching light’s impact on the environment is.

For instance, insects like lightning bugs depend on darkness. The bugs' warm light serves as a form of communication, with different species speaking to each other in specific patterns to find mates. But porch and flood lights can make it hard for the bugs to find one another.

“My passion for dark skies comes from the fact that the natural world depends on it,” Blaine said. “There’s beauty in night ecology. Even if we’re not outside experiencing it, it’s just as important as daytime ecology.”

After discovering a dearth of data in the light pollution research community, Walczak began studying the issue in 2015 as part of the planetarium’s Far Horizons program.

To begin closing the gap in information, Walczak leads volunteers and students in conducting high-altitude balloon missions in which the balloons carry a camera high into the stratosphere. With the resulting images — a single mission generates between 60,000 and 70,000 photos — the team is looking to create a regional map of light pollution.

Walczak, who is also a board member of nonprofit DarkSky International and co-founder of the local DarkSky Chicago chapter, added that his passion for dark skies also comes from a deep appreciation for our connection to the universe.

“I want people to care about the night and care about the sky,” he said. “It's so rare that any kid these days has ever seen a real natural night sky. You could imagine what that means for just our connection to the universe where we find some feeling of belonging and connection to history. We used to navigate through the stars, and now most of the kids we work with don't even think of looking up in the night.”

The good news is, the solution is relatively simple.

“Of all the environmental challenges we see, it’s the most solvable one,” said Blaine, who is also a DarkSky Chicago member. “And it saves everybody money.”

There are five principles for responsible outdoor lighting that Walczak and Blaine said anyone — including municipalities and businesses — can ask themselves when thinking about their light usage:

  • Is it useful? Light should have a clear purpose.
  • Is it targeted? Using shielding and careful aiming, light should be directed so it falls only where it’s needed.
  • Is it set to the lowest level required? Because some surfaces can reflect more light into the night sky than intended, light users should also be mindful of surface conditions.
  • Is it controlled? Controls like timers or motion detectors can ensure light is available only when it’s needed.
  • Is it warm-colored? Because blue-violet light scatters in the atmosphere and more easily disrupts mammals’ circadian rhythms, lights should be set to warmer colors where possible.

Blaine emphasized that turning down the lights doesn’t mean embracing complete darkness.

“Nobody’s advocating to have to have unsafe conditions or to turn every light out,” Blaine said. “We have the technology to do it right.”

• Jenny Whidden is a climate change and environment writer working with the Daily Herald through a partnership with Report For America supported by The Nature Conservancy. To help support her work with a tax-deductible donation, see

Article Comments
Guidelines: Keep it civil and on topic; no profanity, vulgarity, slurs or personal attacks. People who harass others or joke about tragedies will be blocked. If a comment violates these standards or our terms of service, click the "flag" link in the lower-right corner of the comment box. To find our more, read our FAQ.