Beginning with mysterious disappearance of some bats, an ecological danger is unmasked: The world needs darkness

The Luxor Hotel’s 'sky beam' in Las Vegas. (Illustration by Carson Ellis, The New Yorker)

White-nose syndrome, windmill turbines and climate change have all contributed to bat deaths. In Darkness Manifesto, Swedish ecologist Johan Eklöf's reveals an entirely different threat to bats and humans, which he discovered studying Swedish belfries, reports Adam Gopnik of The New Yorker. "According to Eklöf, most churches in southwest Sweden had bat colonies back in the 1980s, and now most of them don’t. Light pollution, his research suggests, has been a major culprit." Eklöf's Manifesto explains, "District after district has installed modern floodlights to show the architecture it’s proud of, all the while the animals—who have for centuries found safety in the darkness of the church towers and who have for 70 million years made the night their abode—are slowly but surely vanishing from these places.”

Eklöf is an bat expert at Stockholm University. "He is able to tell us authoritatively that, though bats do indeed use natural sonar to echolocate their way around, their eyes see well enough in the dark to help in their navigation," Gopnik reports. "Though the book is written as a sort of Silent Spring manifesto against the ecological devastations of light pollution, its considerable charm depends on the encyclopedic intensity with which he evokes the hidden creatures of the night."

With the creation of artificial light, humans erased some of their own connections with the natural world. Gopnik writes, "Where once human life had its nocturnal rhythms, interrupted only by the dim light of candles and fireplaces, the Earth is now so lit up that, seen from space, it glows like a Japanese lantern. Eklöf writes, 'artificial light, the polluted light, is now dominant—light that causes birds to sing in the middle of the night, sends turtle babies in the wrong direction, and prevents the mating rituals of coral in reefs, which take place under the light of the moon.'”

Often extreme light pollution is "not some helpful harborside lighthouse but the 'sky beam' atop the Luxor Hotel in Las Vegas. Creating forty-two billion candlepower of light every night, meant merely as a come-on to tourists and gamblers, it unintentionally excites and undoes flocks of birds, genetically programmed by evolution to fly toward bright light—and, in 2019, attracted clouds of grasshoppers, who flew toward the pseudo-Egyptian pyramid with all the horror of a pseudo-Egyptian plague."

Gopnik adds: "Eklöf insists that doom is still avoidable. 'Light pollution is the easiest of all environmental problems to solve, at least technically,' he writes. 'We, as private individuals, can, with little cost, reduce the amount of our light pollution. With light shades, downward-facing light sources low to the ground, and dim lighting, we can reduce the cities’ total amount of light, as well as the artificial light scattered in the atmosphere.'”

Gopnik reminds us, "The light of reason makes searchlights and lighthouses; the love of darkness asks us to adjust our eyes and egos sufficiently to see as owls do. Seek light in the morning; accept the night when it comes. Then call it a day."