A study conducted by an international team of researchers raises concerns about the worldwide impact of worsening light pollution.
The study found that the parts of Earth with artificial lighting at night grew by a little over 2 percent annually from 2012 to 2016. The brightness of this lighting also increased about 2 percent.
A report on the study in the November issue of the scientific journal, “Science Advances, explained how light pollution was measured and said most of the increase resulted from cities in developing nations adding outdoor lighting as they grew. The researchers identified artificial light as an environmental pollutant.
Like other types of pollution, the adverse impact of excessive artificial nighttime lighting on natural systems is worldwide. In this case, researchers found that introducing artificial light into the nighttime environment on a massive scale disrupts natural systems that are based on living partly in darkness.
The report said this disruption threatens biodiversity, migration and reproduction habits for a wide range of creatures and plants and could threaten humans. Some 30 percent of vertebrates and 60 percent of invertebrates in the world are nocturnal animals.
Although the study didn’t find that the portion of the U.S. that was artificially lit at night from 2012 to 2016 increased overall or that it grew brighter, this varies in different parts of the nation.
Dr. Daniel Caton, a professor in Appalachian State University’s Department of Physics and Astronomy, has been a leading voice for reducing light pollution for decades.
As ASU’s director of observatories, he is in charge of the university’s Dark Sky Observatory in far northern Wilkes County.
Light pollution creates a glow in the night sky that makes it harder to view stars and planets. Because of this permanent glow, many Americans live with little awareness of the beauty and wonder of the night sky.
Caton has worked with local governments in Wilkes and other counties to seek ordinances regulating outdoor lighting. His efforts years ago with the Boone Town Council were successful, but not with the Wilkesboro and North Wilkesboro governing bodies.
Caton and others interested in protecting views of the night sky advocate for outdoor lighting that is directed downward and is shielded to avoid illumination toward the horizon or the sky. He said this also is safer for motorists because it reduces glare. Look for “full cutoff” lighting.
Other basic points to help reduce light pollution – and often reduce expenses - include only lighting areas that need to be lit, only turning on lights when they’re needed, using lights that are no brighter than necessary and avoiding using blue lights because their light waves scatter and spread more.
According to the report in “Science Advances” on the study of artificial outdoor lighting from 2012 to 2016, a growing preference for LED outdoor lights has worsened light pollution because LED lights usually produce blue lighting. Caton noted that a new type of LED light is less blue.
He says lighting that is less polluting also tends to be more effective.