Hello Darkness, My Old Friend!
In the twilight, that nest in the old church of Suntak in Sweden fly around hunting for insects. The twelfth century church’s façade stays unlit at night — a rarity among historic churches — and the darkness continue to make it a sanctuary for the remarkable creatures evolved for the night. You want those bats in the belfry!
In his book The Darkness Manifesto, first published in Swedish two years ago, Johan Eklöf — bat scientist and conservationist — argues that when artificial light burns around the clock, whether in cities, the countryside, or offshore, it disrupts the circadian rhythm of every living being. Nocturnal animals suffer the most, but few creatures on the planet remain untouched by excessive illumination.
Early in the 21st century, astronomers were the first to sound the alarm about light pollution. To measure how much stray illumination washed over observing sites, they created the Bortle scale, ranging from 1 (none, as in the middle of the ocean) to 9 (inner-city level). They also named skyglow, a term that sounds poetic but isn’t — it’s the diffuse brightening of the night sky caused by artificial light. Skyglow obstructs the work of professional astronomers and dims an urbanite’s view of the stars, as if a careless individual had “used a dirty cloth to wipe the window facing the universe,” Eklöf writes.
Biologists started studying how always-on artificial light disrupts organisms. Some life forms that take their time cues from the moon were the first to show unmistakable signs of disorientation: newly hatched turtles crawling toward a streetlamp and doom, for instance, instead of the sea. And as the research grows, it’s becoming clear that light pollution doesn’t just unsettle individual species — its effects ripple through entire ecosystems.
Take the case of insects — nearly 40 percent of species are now at risk of extinction. Anyone who has watched an insect spiral toward a bulb knows how powerfully artificial light can pull them off course. Moths, being nocturnal, are especially vulnerable. In the pre‑industrial era they were proverbially drawn to flames; today they are fatally drawn to bright lights. And because nocturnal moths pollinate as widely — and often more diversely — than daytime bees, their decline sends trouble rippling through the plants that depend on them.
What of humans themselves, the creators of electrical lighting? White light, from LEDs and fluorescent bulbs, has a greater proportion of blue wavelengths compared to incandescent bulbs. Over-exposure to this blue-tinged light has been linked to human ailments ranging from disrupted sleep patterns to a greater incidence of hormone-sensitive cancers.
Recognizing these risks, Sweden’s Karlstad Central Hospital has invested in indoor lighting that mimics the natural shifts in daylight — changes in both color and intensity across the day. The results have been promising, and Eklöf points to this model as evidence that thoughtful design can help restore our circadian balance. With the right light at the right time, he suggests, we can meet our need for brightness without sacrificing our need for darkness.
LEDs — inexpensive, energy‑efficient, and responsible for the explosion of outdoor lighting — may also offer a way out of our excesses, Eklöf writes. Unlike incandescent bulbs, today’s LEDs can be tuned and programmed with remarkable precision. With greater awareness, sensible legislation, and better‑designed fixtures — motion‑activated lights, downward‑facing sources, and other targeted solutions — we can sharply reduce the amount of artificial light that spills into the night sky.
Light pollution may have a straightforward technical fix, but other forces run deeper. Across our evolutionary history, humans have feared the dark, and in many cultures light has come to stand for safety, prosperity, even virtue. Eklöf traces this lineage in succinct chapters that braid psychology, philosophy, and politics to explain how illumination spread so rapidly and so uncritically.
From ancient mythologies to modern religion, he notes, God evokes the light, is the light, and embodies all that is good. Darkness, by contrast, is cast as a literal, moral, and metaphorical enemy — as if “its proximity is an assault to our existence.” Changing that instinctive bias, he suggests, will be far harder than changing the bulbs.
But even before you finish this book, some evening you will step outside at dusk — the Scandinavian landscapes still lingering in your mind — and notice your own neighborhood anew. All at once, the wasteful spill of light will stand out in sharp relief. The final chapter, a true manifesto, offers practical ways to befriend the darkness, which, the author assures us, is “merely a train trip, a walk, or a turned-off phone away.” He urges us to watch how the sun yields to the moon and the stars, to take ourselves into the deep nights of midwinter, and, if we can, toward the mythical northern lights.
From turning off lights when we leave a room to letting our backyards rest in darkness, each small act helps reclaim a night that has grown too bright. And for those who feel moved to go further — to advocate for better lighting policies or challenge the excesses in their own communities — Eklöf offers a path into activism. The planet may be spottily lit, but still far brighter than it needs to be — restoring the darkness is within reach.
The fix is simple: turn off the lights. The harder task is cultural. Until we stop fearing the dark, bats, moths, and even our own bodies will pay the price.
A version of this appeared in the New Scientist. pdf
P.S.
This book rewired my reading habits. I’ve started tracking how writers use light — not just the obvious mentions of lamps or sunsets, but the subtler calibrations of brightness and shadow that shape a scene’s emotional temperature. The best writers wield light like a tool, adjusting it with an artist’s precision to make an image endure.
YiYun Li’s “A Clean Well-Lighted Place” written in 2011.
Equally astonishing was American lighting: in many places, lights stayed on from morning till night. At home, our family, conscious of saving every penny, would not turn on a single lamp until the last ray of daylight had vanished. Lights in public places were sound-controlled. The residents in our building had developed the habit of clapping or stomping to turn on a lamp, and to announce their presence; a few, like me, preferred a stealthy, unnoticeable passing in the dark. How does one live in such a well-lighted country?
KC Grifant’s “All Aboard” written in 2022
The city lights teemed, sending a flood of crimson and violet colors along the dirty harbor water.
listening in 2026 and will hopefully translate sections of it soon.