Environmental Almanac: It's time to take light pollution seriously

Environmental Almanac: It's time to take light pollution seriously

This column is intended as a follow-up to News-Gazette reporter Tracy Crane's recent article on the application to have the Middle Fork Forest Preserve in northeast Champaign County certified as a Dark Sky Park. Her article focused on the direct benefits to people of having a place to see the night sky unobscured by artificial light.

Most people understand that various products of human activity have the potential to harm wildlife when they're released into the world, whether that's into the air, a body of water or the ground. We routinely call these products "pollutants." Fewer people are accustomed to thinking of carelessly spread artificial light that way, but a growing body of evidence makes it clear we should.

To date, the poster critters for the campaign to change the way we think about careless lighting are sea turtle hatchlings. As they emerge from nests on the beach, they can become disoriented by lights on beachfront structures and wander toward them rather than sprinting directly toward the surf. This increases their risk of being eaten by predators or being caught on the beach and overheating when daytime comes around.

Of course, in central Illinois, we have no sea turtle hatchlings to concern ourselves with as we manage our exterior lighting. But we do have other wild creatures, and light pollution affects them, too.

Take birds, for example. Many of them migrate at night, relying as they do on cues that can be obscured by artificial light. We've seen their bodies litter the sidewalks beside tall buildings where lights are left to shine out of windows at night, and we've seen as well that simple changes in our practices can alleviate the problem. Turn out the lights or block the windows, and far fewer birds run into the buildings.

In a study published last fall, researchers found that the impacts on migrating birds of the annual tribute in lights to the victims of the 9/11 attack in Manhattan abated almost instantly when the lights were turned off.

The tribute is created by training powerful searchlights into the sky to create columns of light resembling the towers of the World Trade Center.

Researchers had observed that migrating birds in the vicinity were drawn to the lights and then became disoriented, slowing down, flying close together and in circles, and calling frequently.

By monitoring bird densities in the area and, when those get too high, simply turning off the lights for 20 minutes, researchers and organizers of the tribute have been able to protect the birds and conduct the memorial at the same time.

The effect of artificial light on night-flying insects has also been the subject of an important recent study.

Scientists in Switzerland found that nocturnal pollinators visited a certain type of flower in plots illuminated by streetlight-like LEDs less than half as often as plots that remained dark at night.

As a result, the flowers in the lit plots produced less seed than the others, raising the possibility of cascading negative effects, since those flowers are also a source of food for the pollinators.

Two things are worth keeping in mind as we move beyond our laissez-faire approach to light pollution. One is that it's reasonable to proceed on the assumption that artificial light has negative effects on wildlife and ecosystems without waiting to tease out precisely what all of them are. I say that simply because a certain amount of darkness constitutes one of the defining conditions under which we and the life around us have evolved.

The other thing worth remembering in this context is that there is no upside to light pollution, no constituency that benefits from it. Lights that shine up into the sky or across the landscape waste electricity and serve no good purpose — who needs that?

For more information about the value of dark skies and to learn how you can help combat light pollution, start at the website of the International Dark Sky Association, darksky.org.

Rob Kanter is a lecturer and academic adviser with the UI School of Earth, Society and Environment. You can reach him via email at rkanter@illinois.edu. Environmental Almanac can also be heard on WILL-AM 580 at 4:45 and 6:45 p.m. Thursdays.

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