European Monuments Are Going Dark. Could It Be a Good Thing?

Last week, Paris officials announced the Eiffel Tower’s gleaming lights would start going dark earlier than usual each night—11:45 PM instead of the usual 1:00 AM. The move arises from the ongoing energy crisis in Europe, provoked by a Russian squeeze on natural gas supplies in response to Western sanctions imposed after the invasion of Ukraine. As gas and energy prices soar up to 12 times higher than usual throughout the continent, Paris is aiming to reduce its energy usage by 10 percent this winter. 

While dimming one of France’s most beloved landmarks earlier than usual is more symbolic than a solution—it will only reduce energy use by four percent—the plan has resurfaced conversations about the negative effects of light pollution. More than 80 percent of the world’s population—including 99 percent of Europeans—live under sky glow, which shrouds large urban centers in an orange haze due to excessive artificial light emitted by cars, streetlights, billboards, and buildings. (In places like Mexico City and Las Vegas, it’s so intense that people can read books outside at night.) Sky glow can be five to ten times brighter in cities compared to the world’s most remote regions like Siberia and the Amazon Rainforest.

Sky glow is just one symptom of light pollution: the presence of unwanted or excessive artificial lighting. It can range from the discomfort of pesky street lamps disrupting your sleep to the obstruction of the Milky Way galaxy. Widespread efforts to address light pollution didn’t emerge until the global dark-sky movement took hold in the 1980s, when astronomers noticed nocturnal sky glow was obscuring their view of the stars. The organization has since launched education and advocacy organizations worldwide to reduce the harmful effects of light pollution on the environment, well-being, and safety. 

The negative impacts aren’t limited to astronomy. Much like microplastics infecting our waterways and carbon emissions creating holes in the ozone layer, unwanted light can wreak havoc on the environment if left unchecked. Glass-clad buildings account for one billion annual bird deaths in the United States—many lured off their migratory paths by interior lights shining after dark. Exposure to light while sleeping can suppress melatonin production and cause sleep disorders, headaches, fatigue, stress, and anxiety. Studies show that ambient light deters nocturnal insects from pollinating cabbage thistle plants, which are bearing less fruit and can thus strain supply chains. Baby sea turtles, which hatch at night on the beach, instinctually locate their future sea habitat by spotting brighter horizons over the ocean, but can be led astray by nearby illuminated roads. Millions of sea turtle hatchlings die this way every year in Florida alone. 

It’s difficult to point fingers at a particular culprit when light seems to have overtaken most of the world like a spiderweb, but Scientific American blames unquestioned development and plain human ignorance. Campaigns to restore the dark sky often gain little steam, though multiple U.S. states are exploring legislation to turn off lights during bird migration season. Municipal excuses for inaction often lie in crime prevention, in particular a 2016 study in which criminologists installed nearly 400 giant lighting towers on public space surrounding New York City housing projects. Crime around the towers dropped 45 percent at night, but dark sky researchers questioned the ethics of subjecting minority communities to prison-like floodlights after dark.

Despite the pushback, multiple states across the U.S. are considering dark sky–friendly legislation. As the energy crisis continues to unfold in Europe, bold policies to reduce energy expenditures are afoot. Germany has developed a legal action plan to reverse light-induced insect decline, with Berlin manufacturer Holder Lab developing prototype lights that don’t emit wavelengths disruptive to most insects. A recently passed French law bans businesses from leaving decorative signs illuminated all night. 

“Reducing light pollution is in some ways at odds with modern Western culture—especially when it comes to outdoor advertising and other commercial lighting,” writes author Joe Kissel. “No one is arguing that cities and towns would be safer or better places to live if the streets were completely dark. But even while we teach our children not to be afraid of the dark, we do our best to surround ourselves with light. Perhaps a bit more darkness wouldn’t be such a bad thing. It could turn out to be healthier and safer, not to mention providing some much-needed perspective.”