INCREASING YEARLY
I actually didn’t expect it to be 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 night-time 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, Netherlands, Spain and the United States, although the researchers said the satellite sensor’s “blindness” to some LED light might mask an actual increase.
Australia’s lit area decreased due to wildfires. Night-time light declined in war-hit Syria and Yemen.
Ecologist Franz Hölker, of Germany’s Leibniz-Institute for Freshwater Ecology and Inland Fisheries, said light pollution had ecological consequences, with natural light cycles disrupted by artificial light introduced into the night-time environment.
Increased sky glow could affect human sleep, he said.
“In addition to threatening 30 per cent of vertebrates and over 60 per cent 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.”
Kyba said night-time lighting obscured the stars that people had witnessed for millennia.
Experts had hoped the growing use of highly-efficient LED lighting might lessen energy usage.
The new findings indicate use of traditional lighting instead was growing, increasing energy demand.
“While we know that LEDs save energy in specific projects, for example when a city transitions all of its street lighting from sodium lamps to LEDs, when we look at our data at the national and global level, it indicates that these savings are being offset by either new or brighter lights in other places,” Kyba said. Reuters