Why Light Pollution Is a Much Bigger Deal Than Not Being Able to See Stars at Night

Light pollution eliminates much of the night sky, and with harmful effect.

A lesser long-nosed bat feeds on an agave blossom in Tucson, Arizona. The city is working to reduce nighttime light pollution to help nocturnal pollinators.
Photo Credit: Danita Delmont/Shutterstock

Have you ever seen the Milky Way? The very galaxy we are a part of? I have. But I had to go to Uyuni, Bolivia, to see it with the naked eye. Light pollution eliminates so much of our night sky it’s easy to forget we’re a part of a galaxy, and a universe, that is so much greater than ourselves.

That’s where the Dark Sky movement comes in: Efforts to reduce light pollution here in the United States and across the globe.

According to a recent study, “Earth’s artificially lit outdoor area grew by 2.2% per year” from 2012 to 2016, “with a total radiance growth of 1.8% per year. Continuously lit areas brightened at a rate of 2.2% per year.”

What that means for most of us is that light pollution is growing, and impacting humans and animals in negative ways.

For example, if you think those bright new streetlights are making it harder to see at night when you drive, you’re right. The American Medical Association has the proof. And while the AMA recommends street lighting that does not exceed 3,000 Kelvin, cities including Seattle and New York have LED street lights that exceed 4,000 to 5,000 Kelvin, with short waves that can cause damage to the retina. New research even suggests that light pollution can increase the risk of cancer.

Humans aren't the only ones impacted by artificial light, which kills seabirds, interferes with migrating birds and causes nighttime pollinating insects to stop pollinating. Even fireflies and sea turtles are negatively impacted by our bright lights.

“Protecting the night sky from light pollution is a critical mission that supports human health,” says Amanda Gormley, communications director of the International Dark Sky Association. It also “preserves wildlife habitat, and provides visual access to celestial objects for professional and amateur astronomers alike. Since the beginning of time, we have relied on the night sky to amuse ourselves with stories, find our way, and find a sense of place in the world.” 

Not to mention the tourist dollars generated by astrotourism: Gormley says tourists visiting a place to see the night sky are more likely to stay overnight, and for multiple days, generating more money for the local economy. 

Tucson, Gormley says, “is doing an exemplary job of reducing light pollution. Despite significant population growth, light pollution has increased only minimally, thanks to well-designed lighting ordinances. Tucson requires that lights be shielded [pointed downward], and there is a color temperature threshold requirement. Lights are consistently colored. Everywhere you drive, you see that the lights are a warm, yellow color.”

But don’t darker environments foster crime? “Nope,” says Gormley. “We have found that there is no marked increase in crime when more [responsible] lights are present. In fact, well-placed, shielded lights with minimal glare are better for visibility. This works for drivers and homeowners alike. It's harder for criminals to hide in the shadows when there is less contrast in light.” 

The problem is municipalities are installing the cheaper LED lights at over 3,000 Kelvin, and because they are saving money on lights and energy, “they put that savings into more lights,” Gormley says. “The assumption is that more light is better. It’s not. Responsible light is best” such as shielded light and below 3,000 Kelvin is best.

The good news is LED technology is improving. “There’s different types of LED light. So the bright blue and white LED are a problem, but the lower coordinated color temperatures are better and more pleasant to be around.”

Motion-controlled dimming options, she adds, are being implemented in places like Norway, where roadway lighting increases when a vehicle appears and dims when it has passed.

New local ordinances can effectively help to reduce light pollution. Often, Gormley says, the majority of legal complaints about too much artificial light are made by residents against corporations, and are regularly thrown out of court because local ordinances protect the businesses, not the individual. “These ordinances are supposed to be so the community works for everybody.”

So turn the lights off when you don't need them, and install outdoor lights with motion-detecting sensors. After all, seeing the night sky should be a piece of what makes a community great.

Find dark sky-friendly lighting and resources.

Valerie Vande Panne is an independent journalist whose work has appeared in the Boston Globe Sunday Magazine, Columbia Journalism Review, The Guardian, Politico, and many other publications.

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