Farewell to night? Light pollution reducing darkness worldwide

By Doyle Rice
22 November 2017
(USA Today) – For most of humanity’s history, the night has meant darkness. That’s no longer the case.
Researchers report the artificially lit nighttime surface of our planet is growing — in both size and brightness — in most of the world’s countries.In a study published Wednesday in the journal Science Advances, scientists said Earth’s artificially lit outdoor areas grew by 2.2% per year from 2012 to 2016.Overall, some 79 nations — mainly in South America, Asia and Africa — experienced a growth in nighttime brightness during those years. Only 16 witnessed a decrease in light, including war-wracked nations such as Yemen and Syria. In 39 countries — including the U.S. — it stayed about the same.“Artificial light is an environmental pollutant that threatens nocturnal animals and affects plants and microorganisms,” the study said. Study co-author Franz Holker of the Leibniz Institute of Freshwater Ecology and Inland Fisheries in Germany said nighttime light has “ecological and evolutionary implications for many organisms from bacteria to mammals, including us humans, and may reshape entire social ecological systems.”According to the International Dark-Sky Association, an organization that combats light pollution worldwide, “the increased and widespread use of artificial light at night is not only impairing our view of the universe, it is adversely affecting our environment, our safety, our energy consumption and our health.”Increases in nighttime light pollution were seen almost everywhere researchers looked, with some of the largest gains in regions that were previously unlit.”I actually didn’t expect it to be so uniformly true that so many countries would be getting brighter,” said study lead author Christopher Kyba of the GFZ German Research Center for Geosciences in Potsdam, Germany.“Light is growing most rapidly in places that didn’t have a lot of light to start with,” Kyba said. “That means that the fastest rates of increase are occurring in places that so far hadn’t been very strongly affected by light pollution.” [more]