Farewell to night? Light pollution reducing darkness worldwide

Doyle Rice | USA TODAY

Show Caption Hide Caption We're lighting up Earth at an alarming rate LED and CFL lights last a long time, and they're cheap. But they're still not slowing the demand for artificial lighting. Video provided by Newsy

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.”

Scientists used images taken from one of the USA's polar-orbiting satellites to study the changes in nighttime light over time. They compared images from October 2012 with those from October 2016.

The findings shatter the long-held notion that more energy efficient lighting would decrease usage on the global — or at least a national — scale.

The growth "is disappointing because we might have hoped that the growing availability of highly efficient, solid-state LED lighting technologies might contribute to a decrease in energy usage worldwide," said Kip Hodges, a professor of earth and space exploration at Arizona State University and an editor at Science Advances.

"Instead, it appears that the use of artificial lighting is expanding rapidly, regardless of the lighting technologies used, in ways that undoubtedly increase energy demand," Hodges added.

Another issue: The instrument on the satellite that was used to detect the light changes is relatively insensitive to blue light. White LED light is rich in blue colors, and so it partially escaped detection. Thus, the study may have actually underestimated the problem of light pollution around the world.

To reduce light pollution, Kyba and his colleagues recommend avoiding glaring lamps whenever possible — choosing amber over so-called white LEDs — and using more efficient ways to illuminate places like parking lots or city streets. For example, dim, closely spaced lights tend to provide better visibility than bright lights that are more spread out.

“Today’s announcement validates the message the International Dark-Sky Association has communicated for years,” said executive director J. Scott Feierabend. “We hope that the results further sound the alarm about the many unintended consequences of the unchecked use of artificial light at night."

Contributing: Associated Press