By Walton-Gray Martin

The City of Austin’s skyline at night. (Photo by Walton-Gray Martin)

Austin — In 1895, the City of Austin erected 31 “moon towers” to provide better lighting for an already dark city. The 165-foot-tall towers were given the name moon towers for their high elevation and natural seeming light. As the years went on, myths emerged claiming the towers caused farmers’ crops to grow both day and night and chickens to lay eggs all day. According to the Austin Public Library, these light pollution myths were never supported by facts. Only 17 of these towers remain today, but as Austin continues to grow, so does the city’s light pollution.

According to a recent study published in Science Magazine, from 2012 to 2016 the Earth’s global light pollution grew by 2.2 percent annually. Those who look to the night sky will continue to see more and more stars disappear with the increase in artificial light. John Barentine, a program manager at the International Dark Sky Association, pointed out that light pollution can cause major economic and health problems that we do not even realize. However, these problems can be solved, according to the IDA.

But to understand how to fix these problems we must first understand what causes light pollution. Light pollution is defined by Barentine as any sort of unintended light exposure that has negative consequences. Simple aspects such as the color or intensity of the light can cause pollution.

“As a symptom [light pollution] manifests in different way,” Barentine said. “Sky glow, which is the glow that prevents us from seeing the stars, but there are other effects on the ground like glare. You get into a dense urban environment and you kind of have light coming from every direction or its shinning in your window as you’re trying to sleep. All of those things are consistent with what I’d call light pollution.”

Light pollution map of Texas provided by http://darksitefinder.com/maps/world.html

Light pollution maps, like the one above, give a good illustration of how far light can reach. White and red mark areas with high light pollution, while dark gray sections are areas with very little artificial light. Experts use a system known as the Bortle Scale to categorize the darkness of a location. The scale ranges from 1 to 9. An area with a 1 rating has truly dark skies, while a rating of 9 indicates an urban area such as Austin.

Light reaches so far that Cindy Cassidy, a local amateur astronomer and head of the Texas chapter for the International Dark Sky Association, noticed the sky change one night after a sky scraper in Austin turned it’s lights on. She lives almost 20 miles away.

“One night we were sitting out on our front porch in Driftwood and we go ‘whoa, what just happened?’,” Cindy Cassidy said. “They turned on the lights in the Frost Bank tower at night. It was so awful we drove into town to see what was going on.”

After the lights in the Frost Bank tower were turned on, Cindy Cassidy saw the sky brighten and stars disappear. Light from just one building dramatically changed the night sky for viewers’ miles away. Cindy’s husband John Cassidy, a local amateur astronomer and member of the Austin Astronomical Society, remembers a time when Austin light pollution was not so noticeable.

“I moved here in 1969 and it was a small town then,” John Cassidy said. “Yes, I have seen it change. [Austin is] brighter, the air quality has gone down. That’s part of the night sky too. You have particulates in the air and it reflects [light] down. I have seen it deteriorate significantly.”

Unlike Austin’s moon towers, the increase in light pollution causes major health problems for animals, humans and plants. According to the IDA, nocturnal animals are widely effected by light pollution.

“[Light pollution] gives [nocturnal animals] a false signal as to when to be active or not to be active,” Barentine said. “So right away, that can mess with an animal’s strategy for feeding. They may try to find food at the wrong time of day because there’s light in their environment and they think its daytime. But their food source isn’t available and they may spend a lot of energy for food that’s not there.”

It can also impact animals that eat mostly insects. According to the IDA, artificial light at night often attracts and kills insects. The decline in insect population can undermine the pollination of plants and animals that rely on insects as a food source, like Austin’s bats. On the other hand, for humans, the health effects are not well understood.

“The effect of light pollution on humans in particular — that’s an area that is still maturing in what we know,” Barentine said. “There are some things that we know, but there is a lot that we don’t know right now.”

According to a study published by Harvard in August, women who live in areas with large amounts of light pollution have a higher risk of developing breast cancer. The study concluded that although light pollution may not be the fundamental cause of breast cancer, it could be a major factor. The problem is that our bodies expect light during the day and darkness during the night. But now that we have invented ways to light up the night, our body is exposed to more light than normal. A different study published in 2015 found that this increase in light exposure not only contributes to breast cancer, but also diabetes and obesity.

Wasting light is not just bad for our health, but also our wallets. According to Cliff Kaplan, dark skies program manager for the Hill Country Alliance, one-third of all outdoor light is wasted. That wasted light also means wasted money. In the United States it is estimated around $3 billion a year is wasted on this excess light. In Texas alone it is estimated to cost close to $250 million a year, according to Kaplan. Simply turning off outdoor lights not only protects the night sky and saves money, but it can even serve as a tourism incentive.

“It’s really an economic boom for some of these small towns,” John Cassidy said. “The cities around here are getting a lot of response — particularly Fredericksburg, Llano and Dripping Springs.”

Texas Hill Country towns such as Dripping Springs, Fredericksburg and surrounding communities are considered the most active areas in the world for dark sky conservation, according to Kaplan.

An economic analysis of the impact of dark skies on the Colorado Plateau by Missouri State University illustrates just how important a dark sky is to some tourists. In the late 2000’s roughly 65 percent of Colorado Plateau visitors believed a dark sky was important. In 10 years it is estimated that tourists, in the Colorado Plateau, will spend close to $2.5 billion “trying to see a dark sky at night.”

At the end of the day, the solution to all problems caused by light pollution is simple: turn off the lights.

“Every single light that shines outdoors can make an impact,” Cindy Cassidy said.

Everyone can help reduce light pollution. Cindy Cassidy recommends evaluating the lights used around a location. If you can directly see the light bulb when outside, that is a problem. Lights should be properly shielded to ensure the light is being directed toward the surface it is meant to light. She also recommends using warmer colors and also just simply turning off your lights.

Walton-Gray Martin is a sophomore studying journalism at the University of Texas at Austin.