Energy-saving LEDs boost light pollution worldwide

MIAMI: They were supposed to bring about an energy revolution, but the popularity of LED lights is driving an increase in light pollution worldwide — with dire consequences for human and animal health, researchers said Wednesday.
The study, in the journal Science Advances, is based on satellite data showing that the Earth’s night is getting brighter, and artificially lit outdoor surfaces grew at a pace of 2.2 percent per year from 2012 to 2016.
Experts say that’s a problem, because nighttime lights are known to disrupt our body clocks and raise the risks of cancer, diabetes and depression. As for animals, these lights can kill — whether by attracting insects or disorienting migrating birds or sea turtles. The issue isn’t just the LED lights themselves, which are more efficient because they need far less electricity to provide the same amount of light, explained lead author Chris Kyba, a physicist at the German Research Center for Geosciences. Rather, it’s that people keep installing more and more lights, he told reporters on a conference call to discuss the research.
“We’ll light something that we didn’t light before, like a bicycle path though a park or a section of highway leading outside of town that in the past wasn’t lit,” he said. “And so all of those new uses of light offset, to some extent, the savings that you had.” Experts call this the “rebound effect,” and it can be seen with fuel-efficient cars, too. People may buy a car that requires less fuel, then decide to drive it more often or move further from work, lengthening their commute. - First global night view - The study was based on the first-ever radiometer designed especially for nightlights — the Visible/Infrared Imager Radiometer Suite (VIIRS).
The VIIRS is mounted on the a National Oceanic and Atmospheric Administration (NOAA) satellite named Suomi NPP, which has been orbiting Earth since October 2011. Researchers only analyzed nighttime lights during the months of October, to avoid any increase from holiday lights. “With few exceptions, growth in lighting occurred throughout South America, Africa, and Asia,” said the report. Declines in lighting were rare, but were noticeable in war-torn places like Syria and Yemen. Some of the world’s brightest areas, including Italy, Netherlands, Spain and the United States, were all relatively stable.