Bright but bad future: light pollution rises on a global scale

Researchers said on Wednesday that satellite data showed that Earth’s artificial lighting of the outdoor surface at night grew by about 2 percent annually in brightness and area from 2012 to 2016, underscoring concerns about the ecological effects of light pollution on people and animals.

The rate of growth observed in developing countries was much faster than in already brightly lit rich countries.

The researchers said the US National Oceanic and Atmospheric Administration weather satellite data may understate the situation because its sensor cannot detect some of the LEDlighting that is becoming more widespread, specifically blue light.

“Earth’s night is getting brighter. And I actually didn’t expect it to be so uniformly true that so many countries would be getting brighter,” said physicist Christopher Kyba of the GFZ German Research Centre for Geosciences, who led the research published in the journal Science Advances.

With few exceptions, growth in nighttime light was observed throughout South America, Africa and Asia. Light remained stable in only a few countries. These included some of the world’s brightest such as Italy, the Netherlands, Spain and the United States, although the researchers said the satellite sensor’s “blindness” to some LED light may mask an actual increase.

Australia’s lit area decreased due to wildfires. Nighttime light declined in war-hit Syrian and Yemen.

Ecologist Franz Hölker, of Germany’s Leibniz-Institute for Freshwater Ecology and Inland Fisheries (IGB), said light pollution has ecological consequences, with natural light cycles disrupted by artificial light introduced into the nighttime environment. Increased sky glow can affect human sleep, he noted.

“In addition to threatening 30 percent of vertebrates that are nocturnal and over 60 percent of invertebrates that are nocturnal, artificial light also affects plants and microorganisms,” Hölker said. “It threatens biodiversity through changed night habits, such as reproduction or migration patterns, of many different species: insects, amphibians, fish, birds, bats and other animals.”