By Will DunhamWASHINGTON, April 8 (Reuters) – Daily satellite observations have revealed a continued nighttime brightening globally due to artificial lighting, with important regional variations including a surge in sub-Saharan Africa and Southeast Asia alongside a deliberate dimming in Europe driven by concerns over energy conservation and light pollution.Researchers documented a 16% net increase in global nighttime light from 2014 to 2022, but showed it was not a steady brightening but rather a patchwork of increasing and decreasing regional brightness shaped by numerous factors. The United States in 2022 had by far the highest total luminosity of any country, followed by China, India, Canada and Brazil.AdvertisementAdvertisementBrightening was found to be propelled mainly by rapid urbanization, infrastructure expansion and rural electrification.Dimming, however, had two very different drivers. Abrupt dimming was usually caused by natural disasters, power grid failures and armed conflicts. Gradual dimming was often deliberate, guided by government regulations, transitions to energy-efficient LED lights and efforts to cut light pollution.”For decades, we’ve held a simplified view that the Earth at night is just getting steadily brighter as human population and economies grow,” said Zhe Zhu, a professor of remote sensing and director of the University of Connecticut’s Global Environmental Remote Sensing Laboratory, senior author of the study published on Wednesday in the journal Nature.”We discovered that the Earth’s nightscape is actually highly volatile,” Zhu said. “The planet’s lighting footprint is constantly expanding, contracting and shifting.”AdvertisementAdvertisementThe researchers used more than a million daily images obtained by a U.S. government Earth-observation satellite and processed by NASA. Previous global studies relied mostly on annual or monthly composite satellite images.The most dramatic brigh …
