About the only places with dramatic declines in night light were in areas of conflict like Syria and Yemen, the researchers found. Australia also reported a noticeable drop, but that’s because wildfires were raging early in the study. Researchers were unable to filter out the bright burning light.
Asia, Africa and South America, for the most part, saw a surge in artificial night lighting.
More and more places are installing outdoor lighting given its low cost and the overall growth in communities’ wealth, the scientists noted. Urban sprawl is also moving towns farther out. The outskirts of major cities in developing nations are brightening quite rapidly, in fact, Kyba said.
Other especially bright hot spots: sprawling greenhouses in the Netherlands and elsewhere.
Photos taken by astronauts aboard the International Space Station also illuminate the growing problem.
Franz Holker of the Leibniz Institute of Freshwater Ecology and Inland Fisheries in Berlin, a co-author, said things are at the critical point.
“Many people are using light at night without really thinking about the cost,” Holker said. Not just the economic cost, “but also the cost that you have to pay from an ecological, environmental perspective.”