More than 80 percent of the world and more than 99 percent of the U.S. and European populations live under light-polluted skies, according to a study and new global atlas of artificial night sky brightness published today in the journal Science Advances.
This image of the continental United States at night is a composite assembled from data acquired by the Suomi NPP satellite in April and October 2012. The image was made possible by the satellite’s ‘day-night band’ of the Visible Infrared Imaging Radiometer Suite (VIIRS), which detects light in a range of wavelengths from green to near-infrared and uses filtering techniques to observe dim signals such as city lights, gas flares, auroras, wildfires and reflected moonlight. Image credit: NASA Earth Observatory / NOAA NGDC.
“I hope that this atlas will finally open the eyes of people to light pollution,” said lead author Dr. Fabio Falchi, a researcher at the Light Pollution Science and Technology Institute in Italy.
“The new atlas provides a critical documentation of the state of the night environment as we stand on the cusp of a worldwide transition to LED technology,” he added.
“Unless careful consideration is given to LED color and lighting levels, this transition could unfortunately lead to a 2-3 fold increase in skyglow on clear nights.”
According to the atlas, the Milky Way is hidden from more than one-third of humanity, including nearly 80 percent of North Americans and 60 percent of Europeans.
Moreover, 23 percent of the world’s land surfaces between 75°N and 60°S, 88 percent of Europe, and almost half of the U.S. experience light-polluted nights.
“We’ve got whole generations of people in the U.S. who have never seen the Milky Way. It’s a big part of our connection to the cosmos – and it’s been lost,” said co-author Dr. Chris Elvidge, from NOAA’s National Centers for Environmental Information.
“Residents of India and Germany are most likely to be able to see the Milky Way from their home, while those in Saudi Arabia and South Korea are least likely,” the scientists said.
Light pollution is most extensive in countries like Singapore, Italy and South Korea, while Canada and Australia retain the most dark sky.
In Western Europe, only small areas of night sky remain relatively undiminished, mainly in Scotland, Sweden and Norway.
Despite the vast open spaces of the American west, almost half of the U.S. experiences light-polluted nights.
“In the U.S., some of our national parks are just about the last refuge of darkness – places like Yellowstone and the desert southwest,” said co-author Dan Duriscoe of the National Park Service.
“We’re lucky to have a lot of public land that provides a buffer from large cities.”
In 2001, Dr. Falchi was part of a team of researchers who produced a similar atlas.
The new atlas takes advantage of low-light imaging from the NOAA/NASA Suomi National Polar-orbiting Partnership (NPP) satellite, calibrated using data from ‘Sky Quality Meters’ at 20,865 individual locations around the world.
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Fabio Falchi et al. 2016. The new world atlas of artificial night sky brightness. Science Advances, vol. 2, no. 6, e1600377; doi: 10.1126/sciadv.1600377
