For most of human evolution, artificial light came from fire. Then along came electricity and the world has never been the same, a development that has scientists concerned.
Medical physicians are seeing disruptions in sleep cycles and circadian rhythms, botanists are seeing alterations in plant growth, but astronomers have been sounding the alarm bells for years. Bill Wren, called “The Angel of Darkness” for his passionate pleas to preserve the skies of west Texas, is key among them. He’s a public affairs specialist with UT Austin’s McDonald Observatory, and cites four key issues. “Dark sky preservation, cost efficiency, safety and security to help improve visibility, and then the questions of health as we recognize what happens to our bodies with too much light at night.”
To determine how quickly use of artificial light is spreading across the planet, an international team of scientists used infrared technology to measure the brightness for four consecutive Octobers from 2012 to 2016. They find it’s increasing by 2.2% each year, mostly in developing regions like Asia and Africa.
Wren says outdoor lighting must always be pointed downward. It’s a complete waste to do otherwise. LED lights, which are more efficient, can be part of the solution, but some scientists caution that cheaper light often leads to more of it being used, not less.