Mother Jones
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A country whose capital, Paris, made history with its “City of Light” glowing streets is suddenly trying to dial them down. Starting this summer, a French decree mandates that public buildings and shops must keep lights off between 1 a.m. and 7 a.m in attempt to preserve energy and cut costs, and “reduce the print of artificial lighting on the nocturnal environment.”
As France’s move suggests, civilization’s ever-growing imprint on the night sky has more than just stargazers concerned. In his new book, The End of Night: Searching for Natural Darkness in an Age of Artificial Light, writer Paul Bogard bemoans how our last dark spaces are slowly being devoured by the “light trespass” of artificial rays. A team of astronomers recently projected that while the US population is growing at a rate of less than 1.5 percent a year, the amount of artificial light is increasing at an annual rate of 6 percent. It’s more than just a nostalgia for primordial darkness that’s eating at Bogard: Too much light causes animals to go haywire, derails natural cycles, and damages human health.
The greatest sources of light pollution in cities worldwide are street lamps and parking lots, partially because we’ve been bred to believe that public lighting equals safety. Take this recent map of the number one 311 complaint of New Yorkers during the summer of 2012; people wig out when there’s a dark bulb on their block.
But there’s a chance we have it all wrong, argues Bogard. In the late ’70s, a US Department of Justice report found no statistical evidence that street lighting reduced crime. More recently, similar findings—such as this 2008 review by California’s public utilities company—have been largely ignored by the general public.
Optometrist Alan Lewis, former president of the Illuminating Engineering Society of North America, argues in the The End of Night that the glare of poorly designed street lamps (“probably eighty percent of street lighting”) can even make it harder to see things at night. Our eyes don’t have a chance to adjust to darker areas, and the extreme contrasts make our night vision poor.
It gets much worse than not being able to see in the dark. Scientists have unearthed troubling links between artificial light and our most feared diseases: obesity, diabetes, cardiovascular risk, and cancer. Apart from preventing people from getting adequate shut-eye, electric light at night has been show to suppress the body’s production of melatonin, which is thought to play an important role in keeping certain cancers, such as breast and prostate cancer, from growing. Potent “blue” lights—such as those used in certain energy-efficient LEDs, and on tablets, cellphones, computers, and TVs—may be the worst culprits. “It turns out that the wavelength of light that most directly affects our production of melatonin at night,” writes Bogard, “is exactly the wavelength of light that we are seeing more and more of in the modern world.”
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