It's Time to (Not) See the Light

Humans have long been captivated by clear, dark skies. Stars have given us the ability to navigate at sea; they’ve shaped religions and traditions; they’ve been a source of inspiration and art; they help us measure time and mark events. That deep black canvas dancing with yellow-ish white speckles and a faint, hazy river of purples and blues that make up our galaxy — it can make the viewer feel small and insignificant, connected to everything and everyone, or a little of both.

Craning our necks to marvel at the spectacle of the sky is something many of us remember from childhood, and in 2025, most of the country was reminded of the magic of the night when we were treated with views of the aurora borealis. While the northern lights were bright enough to see even in town, the real show was reserved for those willing to get in their cars to find the dark. 

Having to leave town to see the sky is a product of our outdoor lighting choices. Humans aren’t naturally nocturnal, and it’s understandable that we pursued illuminating the night to extend our day. But gradually, our desire to see a little better in low light conditions grew into very little tolerance for darkness at all. Published in 2016, the World Atlas of Artificial Night Sky Brightness found that more than 99% of people living in the United States can’t experience a natural night. The lights are so bright that the Milky Way is now hidden from more than one third of the globe. 

maps courtesy of James Bruton, DarkSky Iowa

Light as a pollutant

Started in 1987 by a small group looking to raise awareness in their local community, DarkSky International is now a recognized worldwide authority working to restore the nighttime environment and protect communities and wildlife from light pollution. They define light pollution as "the human-made alteration of outdoor light levels from those occurring naturally." Excess or irresponsible lighting is just as much a pollutant as contaminants in our air, water and land. When we use excessive lighting, lighting that is angled outwards or upwards, lights without a real need or purpose, or lights without timers or motion detectors, we end up with a significant amount of "sky glow." It’s not innocuous: sky glow does more than mask stars and the Milky Way from our view. 

Environmental health

The most thoroughly studied effects of light pollution are in relation to wild animals and plants. The consequences are far reaching, overwhelming and across taxonomies. Prolonged exposure to artificial light is a problem even for plants, leading to a misjudgment of the true length of day and poorly timed leaf or fruit production. Fireflies, which communicate via light, cannot find each other. Pollinators and other insects become confused about how to orient themselves and are drawn to the cool-colored light of street lamps or porch lights. Some species of bats, who feed on those same insects, avoid brightly lit areas and thus have less food availability. Frogs and toads are less likely to call during their mating season. Prey becomes more visible without the cover of darkness, giving predators an advantage. And migratory birds — 80% of whom navigate under celestial light — wander off course, collide with buildings, can’t finish their journey due to exhaustion or mistime their departure or arrival. 

Mitigating and educating about light pollution’s impacts to birds was the main impetus behind Lights Out Iowa, a program spearheaded by concerned Ames residents Lorna Carroll and Laura Beskow. Their initial efforts have been localized but the pair is on the cusp of rolling out a more statewide approach, feeling hopeful and energized by their successful outreach programs, presentations to civic groups and welcomed presence at farmer’s markets and other community events. 

“Research shows we've lost over 30% of birds in North America since the 1970s,” Carroll explains. 

There are a variety of causes, ranging from habitat loss, predation by free-roaming cats, increased pesticide use, and light pollution. Since light pollution is particularly problematic for birds during migration periods in spring and fall, Carroll emphasizes that simple changes in lighting practices “make an instant and positive difference.” 

In nearly every way, from communication and reproduction to navigation and protection, our excess light is having deadly effects on the lives around us. 

Human health 

Our world is awash in electric light, indoors and out. While its effects aren’t as well studied in humans as in wildlife, scientists point to the disruption of our circadian cycle as a real concern. That internal clock is tied to many biological processes like hormone production, brain wave patterns and other processes at the cellular level. 

A growing body of evidence suggests that light pollution suppresses humans’ ability to produce melatonin — a hormone most often associated with falling and staying asleep. It makes sense that light pollution would disrupt our circadian cycle, but melatonin is also important for immune function, and an increasing number of studies are linking suppressed melatonin levels with a higher risk of developing certain cancers and the impaired function of our genes. An association between artificial light and psychiatric disorders, cardiovascular disease and obesity has also been documented. We might not know all the ways in which excess light is affecting our bodies or moods, but one thing is certain now: we are living in more light than we need. 

Economy 

“One of the unique natural resources our small, rural communities have is a natural, dark sky,” explains James Bruton, the mind behind DarkSky Iowa, another statewide initiative launched in late 2025. “In addition to helping preserve community character and rural identity, dark skies have the potential to create real economic benefit to these communities.” 

While Bruton recognizes the effects light pollution has on the health of humans and wild counterparts, his research and outreach efforts have primarily focused on economic impacts. All communities, but particularly rural ones, stand to benefit from prioritizing dark skies. Shielded, downward-directed and motion-triggered lighting is not only more energy efficient — augmenting or reducing municipal lighting would yield cost savings that could be redirected to other public amenities or services — but these changes also strengthen public safety by actually increasing nighttime clarity. 

“Over lighting does not prevent crime or accidents,” Bruton explains. “In many cases, it creates deeper shadows and blind spots.” 

The economic impacts go beyond saving some money on utility bills. He believes that Iowa’s rural landscapes have the potential to become dark-sky destinations, citing a 2019 study that found “…non-local tourists who value dark skies will spend $5.8 billion over the next 10 years in the Colorado Plateau.” While Iowa is outside of this region, the concept translates: tourists on vacation want to visit places with high scenic value. And communities with dark-sky policies report revenue increase across small businesses in lodging, dining, retail or events. 

Protecting Iowa’s natural heritage 

Returning to a more natural landscape has been on the mind of INHF Board Member Mike DeCook for the many years he and his family have spent re-wilding their lands. 

“For me, it’s not just about protecting and restoring Iowa’s land, water and wildlife,” Mike reflects. “It’s also about the sky. I tend to focus on the aesthetics — the beauty and awe of a truly dark sky — as well as the impact to wildlife, but there are many reasons to care about and value wild nature and many ways in which we’d benefit from letting only the day be light. I’m hoping light pollution’s negative impact to fireflies will be the catalyst to an increasing dark sky movement.” 

We can again look up and dependably find clear, dark skies. The solution is simple and affordable. Audit your current lighting practices at home. Ask your employer and neighbors to consider the same. Approach your city officials about using shields or timers on municipal lights or ask about passing an ordinance that would promote dark skies. 

“Light is our most widespread environmental pollutant,” DeCook urges. “It’s also the most easily reversible.”