The moon shines bright on Shepherdstown on Saturday night. Tabitha Johnston

SHEPHERDSTOWN — The Potomac Valley Audubon Society (PVAS) began the new year by moving its monthly program to a new location. On Jan. 9, Dark Sky advocate Jesse Melton spoke about “Light Pollution and What You Can Do About It” in the Robert C. Byrd Center for Congressional History & Education.

Melton spoke on behalf of Bolivar-Harpers Ferry DarkSky, which is a local chapter of the nonprofit organization, DarkSky International, on the problem with light pollution, which he described as “Man-made brightening of the night sky.”

“When I was younger, my father ran a community astronomy program. That’s what really sparked my interest in all of this,” Melton said, mentioning he grew up in Tennessee. “I was always looking up at the night sky, and became acutely aware, over time, of what I wasn’t able to see as more and more lights were put up.

“As I got older and started to travel, it really struck me, how unfair it was that so many people never got to see what was going on over their heads all the time. Something should have been done about it!” Melton said. “That’s ultimately what led me to DarkSky.”

According to Melton, DarkSky operates around the globe through the work of volunteers, advocating for responsible lighting policies and dark sky lighting. Their work is especially important in developed countries like the United States, which tend to have the greatest amount of light pollution. In the U.S., 99 percent of the population lives under light-polluted skies.

“Globally, only two out of 10 people can see the Milky Way — that’s really bad!” Melton said. “There’s this tremendous thing that played this huge role in all of classical mythologies and cultures — the Egyptians and the Greeks and the Native Americans — all of them wrote stories about it. It was a big thing for thousands of years! And over the last 150 years, we’ve lost it.

“There have been several generations of people who have never been able to see it — and you should be able to,” Melton said. “It’s not the only thing we can’t see because of poorly controlled lighting: other planets, comets, meteors, spacecraft and sometimes even the Northern Lights.”

A second, possibly even more problematic result of light pollution, is that it disrupts the natural cycles of every living thing in an effected ecosystem — from plants to pollinators to animals to people. This negatively impacts the health and safety of all members of that ecosystem. For humans, the effects of light pollution can lead to developing mood disorders, obesity, diabetes, reproductive problems, cancers, metabolic abnormalities, a compromised immune system and sleep disorders, according to Melton.

He noted that, with a little bit of effort, light pollution can be decreased.

“What we’re talking about is the difference between responsible and irresponsible outdoor lighting. Nobody’s arguing that we shouldn’t have light — we have to have it! It allows us to see everything we want to and we need to. But we need it to be done in an energy-efficient and safe way,” Melton said. “Some sources are localized and are something you can prevent at home. Others require larger-scale solutions and require more people to get involved.”

DarkSky encourages individuals to follow five steps, Melton said, to cut down on light pollution. First, use light only if it is needed — all light should have a clear purpose. Second, direct light so it falls only where it is needed — use shielding and careful aiming to target the direction of light beams, so they point downward and do not spill beyond where they are needed. Third, use the lowest light level required and be mindful of surface conditions, which may reflect more light into the sky than intended. Fourth, use light only when it is needed, through controls such as timers or motion detectors. Fifth, limit the amount of blue-violet light and use warmer color lights, whenever possible.

To learn more about Bolivar-Harpers Ferry DarkSky, visit https://www.bhfdarksky.org. To learn more about DarkSky International, visit https://darksky.org.