Rail against the light
Artificial light harms our bodies and souls. It doesn’t have to be this way, says
Her first night on Earth, I took my daughter to see the sky. Clouds blocked much of the view, but low above the western horizon a waxing crescent moon glowed amid a handful of attendant stars.
I later learned that newborns are nearsighted and can focus only on objects 20-30cm away. The distance to, say, Dad’s face. But I could not wait to share with her the beauty of the universe.
The sky that night, though, was much diminished from the skies of my childhood in suburban Minneapolis, in the United States. Then, the Milky Way still arced overhead.
In the intervening decades, our northern American city, like nearly every city around the world, became swamped with artificial light. A recent study published in Science sounded the alarm on skyglow.
Ten years ago, I set out what a serious problem light pollution was for the health of people and ecosystems in my book The End of Night: Searching for Natural Darkness in an Age of Artificial Light.
It was a waste of money and energy, I warned, that erased starry nights the world over. Since then, light pollution has grown by a troubling 10% each year, new data shows. In other words, the world’s skies have doubled in brightness in less than eight years.
One big culprit? The tsunami of electronic lighting such as LEDs – barely on the horizon a decade ago – that has washed over the planet.
Too often, city planners assume adding more light is an effective way to address crime. Yet many lights are used in ways – unshielded and shining into the sky, blazing over empty parking lots through the wee small hours – that serve little purpose. While artificial light at night might make us feel safer, there is no clear evidence that it actually improves our safety.
Worse, these lights take a toll on our health. Artificial light at night disrupts sleep cycles, hormones and more. It has been linked to chronic diseases such as obesity, diabetes and some cancers.
The effects on the animal world are equally disturbing. Car headlights and streetlamps have been shown to make almost every species studied less resilient to environmental change, which has impacted foraging and reproduction, for instance.
Light pollution disorients millions of migratory birds and is contributing to the population decline of pollinating insects.
One recent study found that even quite dim light alters where plovers roost and grunion spawn. If exposed to artificial light, trees, grasses and crops might bud early or yield less.
Now, our night skies face their greatest threat: the expected expansion of low Earth orbit satellites from 5000 to more than 100,000 in the next decade.
Bright enough to be visible with the naked eye and to blind the world’s most important research telescopes, these megaconstellations threaten to fundamentally alter humanity’s experience of looking at the stars.
Is all this light an unavoidable cost of modern life? Not at all. In the United States alone, for example, at least 30% of outdoor light is wasted. We can use artificial light more intelligently, and recent developments offer hope we will.
Last year, dark-sky advocates created the Responsible Outdoor Lighting at Night Manifesto in collaboration with influential professional lighting organisations.
It offers designers and manufacturers 10 core principles for external illumination to encourage changes. These suggestions include the use of warmer colours such as red and orange, rather than blue and white, wherever possible and the use of direct light only where needed.
Worldwide, momentum is growing for smarter regulation and policy. At the United Nations, a new dark and quiet skies movement is taking shape. Last year, a promising new policy initiative at the European Union was spearheaded by the Czech Republic.
The city of Pittsburgh recently adopted the most dark-sky-compliant lighting ordinance in the eastern US, while in Mexico night-time lighting is subject to pollution regulations.
With dimmers, movement sensors and more, the tools exist to light our nights differently. What is lacking is public awareness of the steep costs of light pollution and the political will to make smarter decisions about the future.
I have been thinking a lot about the future these days. What will my now-5-year-old’s nights be like when she’s my age? I want her world to be canopied by moonlight and the breathtaking Milky Way.
I think, too, about millions of children in overlit cities who might never know these wonders. Will the future be one where only the uber-rich are able to visit increasingly remote locations to come faceto-face with the universe?
I hope we will choose instead to light our nights in ways that enhance our health and safety, add to the beauty of our communities and inspire us to take our children outside and point to the sky.
While artificial light at night might make us feel safer, there is no clear evidence that it actually improves our safety.