DALLAS, March 29, 2014 — Brightly lit cities are often seen as a sign of progress. For example, the iconic picture of the Korean peninsula at night is often used to show the differences between bright and prosperous South Korea and poorer, repressive North Korea. However, experts say those bright lights are not an unmitigated good. Artificial light spilling from urban areas causes light pollution that affects not only our ability to see the stars, but also our health, the environment, and our wallets.
Light pollution is artificial light coming up from the ground that scatters off of dust or molecules and reflects back down. “It’s most commonly manifested by what we call sky glow—the phenomenon over a typical city where if you’re standing at ground level the sky background isn’t completely dark and you can’t see as many stars as you would in the background,” said John Barentine, program manager at the International-Dark Sky Association.
IDA was founded in 1988 in an effort to conserve the natural night sky by educating people about the existence of light pollution and working toward solutions. Unlike other forms of environmental pollutants that affect resources like water or air, people don’t typically think of light as being a pollutant or the night sky as being a natural resource. But even though the impact of light pollution isn’t readily apparent, it has far reaching effects.
The most visible result of light pollution is the inability to see the stars. Because of sky glow, only the brightest stars are visible in urban areas. The reach of the light pollution from these urban areas brightens the night sky for miles around. Many Americans have no ability to see such phenomenon as the Milky Way, and even bright constellations such as Orion may fade if light pollution increases.
There are other, less visible but more harmful effects of light pollution as well. Researchers are beginning to understand that light pollution has an impact on human health as circadian rhythms are disrupted. For example, in populations such as shift workers that work a lot at night there’s a higher incidence of some forms of cancer.
While the connection between human health and light pollution is not fully understood, the impact on wildlife is well-established. One of the most well-known effects is the impact on sea turtle hatchlings, who instinctively move toward the brightest object when they emerge from the sand, which in natural settings is the sea reflecting the night sky. However, artificial light sources near beaches disorient the turtles and many never find their way to the ocean. Many other wildlife populations are likewise affected by artificial lights.
Another aspect of light pollution is the wasted energy and money. “We emit millions of kilowatt hours a year in electricity in the form of light that’s aimed up at the sky, rather than putting that light on the ground,” said Barentine. “That light heading up into the sky is just like watching dollar signs floating up into the sky at night.”
While the problems of light pollution are wide-spread, the solutions are remarkably simple. “There is a problem,” said Barentine, “but it’s a problem we can solve, and it’s easier to solve than you think.” Unlike other forms of pollution, there is no toxic waste to dispose of with light pollution. The solution is as simple as turning off—or more commonly redirecting—the lights.
Part of the challenge for dark sky advocates is addressing concerns that reducing light pollution would make places less secure because bright lights equate to safer cities. However research doesn’t necessarily suggests over-lighting areas may actually make them more dangerous. Bright lights can make potential victims of crimes more visible while simultaneously creating shadows where perpetrators can hide. Likewise, bright lights in parking lots can illuminate vehicle interiors so thieves can see exactly what people have to steal. Over-lighting may be having the effect of making spaces less safe.
Barentine stresses that the goal of IDA “isn’t to be some kind of light cops that are just trying to get rid of all the light that we use at night. We’re not opposed to people lighting their cities.” IDA does encourage wiser use of lighting that maintains security while reducing light pollution. The organization promotes smart use of light through programs like Fixture Seal of Approval, which designates light fixtures and designs that provide adequate lighting while limiting excess light. On a larger scale, IDA has developed the International Dark Sky Places to promote wise lighting ordinances and community awareness of night sky preservation.
The International Dark Sky Communities are cities and towns that are recognized for their efforts in protecting the night sky. The most recent community to be awarded this designation is Dripping Springs in the Texas Hill Country. While they are only about 25 miles from Austin and experience some of that cities light pollution, they have led the way in protecting the heritage of the night sky, said Barentine. “When people think Texas, they think “The stars at night are big and bright, and that’s true in a large part of the state. They realize that, and they went to lengths to try to protect that.”
Dark Sky Communities aren’t required to be in areas that are already dark. In 2011 Homer Glen, Illinois in the suburbs of Chicago achieved dark sky status. “Their skies are bright at night necessarily because of where they’re located,” said Barentine. “They enacted some good lighting policy with the intent of being a model and showing their surrounding communities that they could adopt similar policies. If everybody did that and you got this critical mass, we think you actually could make inroads even in a place as bright as somewhere like Chicago.”
The other category that IDA promotes is Dark Sky Parks and Reserves. These places are required to be dark to receive that designation. “The process of becoming a dark sky or reserve is similar (to communities) in that they have to show that all of the lighting that’s on the park land is compliant with our standards for being dark sky friendly, and they also have to seek the support of the surrounding communities to ensure that the dark places will stay dark in the future,” Barentine said.
These places are beginning to see a benefit from their efforts. Barentine said for most of them, it’s a value-added aspect. Typically, people don’t come to these areas specifically for the dark skies, but having that component expands how people enjoy the parks and communities. One Dark Sky Park, Galloway Forest Park in Scotland, found that for every pound spent on promoting dark sky tourism they’re getting almost two pounds back in increased economic activity attributable to tourism.
While dark skies alone don’t usually draw tourist, there is a small market for astrotourism. One Dark Sky Reserve has seen benefit solely because of it’s designation. The Aoraki Mackenzie reserve in New Zealand has reported getting tourists from as far away as Japan specifically to see the dark skies there.
Currently there are only six Dark Sky Communities, in part because the program is not yet well-known. However, “the process is meant to be a high bar. The places that make it through are those that have really good, sustained commitment, and they don’t look at this as just a thing to put on their shelf in their town hall, another award,” Barentine said. “We really want them to be engaged, and we want them to stay engaged.”
“Some people have the impression that it’s inevitable that our cities are going to get brighter, there’s nothing we can do about it. But this is a problem that we can solve,” said Barentine. “We can do it without compromising safety and security. It would improve everybody’s quality of life that much more if you’re living in the city but at the same time you can go outside and see the stars at night. That’s what we would like everybody to be able to do.”