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IN THE twilight, the bats that nest in the old church of Suntak in Sweden fly around, hunting for insects. The 12th-century church’s façade isn’t lit up at night. So, as in the past, the building remains a sanctuary for bats, remarkable creatures that have evolved to function in the dark.
In his book The Darkness Manifesto, originally published in Swedish two years ago, Johan Eklöf, a bat scientist and conservationist, makes the case that when lights are on around the clock, in cities, the countryside or even offshore, the circadian rhythm of all beings on Earth changes. While nocturnal animals are the most affected by excessive lighting, few creatures on the planet remain untouched.
Early in the 21st century, astronomers established a to assess the level of superfluous artificial light at observing sites. Sky glow, which significantly affects stargazing, obscures all humanity’s view of the night sky – just as though a careless individual had “used a dirty cloth to wipe the window facing the universe”, as Eklöf writes
Biologists have studied how always-on artificial light disrupts organisms. Some that take their time cues from the sun or moon seemed clearly off: birds singing in the middle of the night, baby turtles heading off in the wrong direction. Research findings on how light pollution affects entire species and ecosystems are still emerging.
Take insects, of which nearly 40 per cent of species face extinction. To anyone who has ever seen an insect react to light, it is obvious that light pollution is a major cause, says Eklöf. Moths, which are largely nocturnal, are particularly vulnerable. In the pre-industrial era, moths were proverbially drawn to flames. Now, they are drawn to bright lights. Like daytime bees, nocturnal moths are pollinators. In fact, they visit more kinds of flowers than bees do – so moth decline is bad news.
What of the creators of electrical lighting themselves? White light from LEDs and fluorescent bulbs has a greater proportion of blue wavelengths compared with incandescent bulbs. Overexposure to this blue-tinged light has been linked to various human ailments, from disrupted sleep patterns to a greater incidence of hormone-sensitive cancers.
Recognising these health risks, Karlstad Central Hospital in Sweden recently invested in indoor lighting that mimics the natural variation in both colour and intensity of the light people would be exposed to outdoors. This successful model, Eklöf writes, suggests we can use thoughtful design to regulate light exposure, meeting our need for both light and darkness.
The LED, an inexpensive, energy-efficient technology that led to a proliferation of outdoor lights, could also be a solution to our excesses, he writes. Today, light can be controlled and programmed in a way that wasn’t possible with the incandescent light bulb. So, with greater awareness, some legislation and a host of better-designed lighting products – motion-activated lights, downward-facing light sources and the like – we can reduce the amount of artificial light that ends up being scattered into the atmosphere.
There are also sociological factors to consider. Throughout our evolutionary history, humans have been afraid of the dark, and culturally, we now consider light as a symbol of prosperity. In succinct chapters, Eklöf lays out the psychology, philosophy and politics behind the spread of illumination. Embracing the darkness isn’t going to be easy.
But even before you finish this book, you will step out of your home at dusk sometime and you will become aware of all the wasteful lighting in your own neighbourhood. Thankfully, Eklöf’s last chapter is a manifesto of actionable points to befriend the darkness, which, he assures us, is “merely a train trip, a walk or a turned-off phone away”. He asks us to notice how the sun gives way to the moon and the stars – and to take ourselves out into the dark nights of midwinter.
From turning off the lights when we leave a room to allowing our backyards to rest in darkness at night, we can all do our bit to try to save this spottily, but still too brightly, lit planet.
Vijaysree Venkatraman is a science journalist based in Boston, Massachusetts
