True Darkness Is Necessary: How Artificial Light Affects Our Environment & Health

Did you know that we have less dark sky in our lives than in previous decades? Perhaps you’ve noticed your neighborhood lights are a little brighter, or that cars that seem to have their bright lights on, always. If you feel something is amiss, you are correct. It wasn’t always this bright. And there is a burgeoning movement to help us return to darkness.

Image from NASA

Years ago I listened to a podcast about the lack of dark sky at night, and each time I’m outside at night, I’m reminded about the loss of our dark skies. The short version is this: we are losing our nighttime skies due to increased artificial lighting at night, and it’s not good for humans or animals.

I’ve chosen to live my adult life on the island of Oahu, where there are good (not great) opportunities to see truly dark sky. Even here in the middle of the Pacific Ocean, there are some great beaches where there is very little light from the city, but there is almost no place on the island where you can truly escape the light pollution. When viewed from the nightime beaches on Molokai, 26 miles across the Ka Iwi channel, Oahu appears as a bright, floating orange orb in the middle of the inky blackness. The light pollution in our little city by the sea is immense, but I was not prepared for what I experienced in Los Angeles, California, last summer. The skies were so bright in the city at night that you could actually see your shadow; it didn’t seem like nighttime at all. It was unbelievably bright, despite the fact that they have undertaken a large LED retrofit for city lighting.

How does one measure the dark sky? There is actually a metric for this called the Bortle Scale. It ranges from 1 (the darkest) to 9 (the brightest). Brightly lit urban centers like Las Vegas or New York City’s Times Square rate at 9. Emmet Fitzgerald, writing for Yes Magazine, says that “it’s almost impossible to find a Bortle Class 1 anymore. [The} darkest skies in the US are in the four corners region, where Utah, Colorado, Arizona and New Mexico meet on the Colorado plateau.”

I’ve experienced some of these dark skies in our wondrous National Parks in the United States, high in mountains or on those few beaches here in the islands, or when at sea, and it deeply saddens me that others don’t get to see this, and further saddens me that this key aspect of our evolution – deep darkness – is increasingly uncommon.

Paul Bogard, author of the book The End of Night, estimates that 40% of those in the US and Western Europe don’t actually get to use our natural night vision –  it’s just not necessary in our overly bright world. This is compounded by the constant blue light emanating from our laptops, cell phones, and most indoor lighting. This excessive blue light is not good for our brains and our bodies. You can avoid excessive blue light exposure by limiting the amount of time on devices before bed (many experts recommend putting away all devices at least two hours before bedtime), and having more soft, orange-hued ambient lighting in the house. Learn more here about what blue light does to our body and how to avoid it. In my house we use smart lights called Hue, giving my house a warm glow (and they are dimmable using the app, for even more ambiance). I also have the program F.lux on my computer, which dims the blue light on the screen after sunset. Usually I turn off my phone a few hours before bed to limit exposure.

There is obviously an energy efficiency argument here, too: using fewer lights to brighten a home or storefront is great, as are retrofits with more efficient lighting. However, many LED lights that help reduce energy use are often too far into the blue light spectrum, potentially putting efficiency needs at odds with human health, as examined in this article. Using reflective shields to point light downwards, or creating ‘lights on demand’ could reduce our exposure to blue lights. Or you could wear the blue-blocking glasses that all the cool biohacker dudes use.

Furthermore, these bright lights are bad for nature too – and it affects nearly all living things, with the hardest hit being insects, an often overlooked key part of our natural ecosystems. This Nature article does a deep dive into which species are affected and how, and generally it’s not good. If the scary stats about ecosystem collapse stats don’t make you want to turn off your spotlights and get your city to reduce lights, I don’t know what will.

Image from NASA

Thankfully, here in the US, there are initiatives to keep our skies darker – with most efforts focused on the US National Parks. In the Yes Magaizine article, Fitzgerald explains that Canyonlands National Park in Utah “has been measured at a Bortle Class 2 and was recently named an International Dark Skies Park — the seventh on the Colorado Plateau.” Another expert notes that this area of the American West has the highest concentration of these types of Dark Skies Parks; at the time of this writing there are nearly 80 Dark Sky Parks (57 of which are in the US). The good news is that it’s growing: when Fitzgerald wrote his article in 2016 there were only 28.

One of the newest additions to this list is the designation of Niue, a small island nation in the Pacific Ocean south of American Samoa, as the first Dark Sky Place. On this small island, bright stars sparkle over the landscape, and the lack of light helps protect wildlife and help bolster tourism – and preserve important Polynesian traditions based on lunar cycles and celestial navigation. Tourism Niue chief executive Felicity Bollen explains that dark sky tourism is a big deal, and it helps the country focus on minimally impactful tourism. “The stars and night sky have a huge significance to the Niuean way of life, from a cultural, environmental and health perspective [and being] a dark sky nation will help protect Niue’s night skies for future generations of Niueans and visitors to the country.”

I’m looking forward to seeing the International Dark Sky Association add more places to their list, and once we’re able to travel again, to add these unique places to my bucket list. You can check out their page to learn more about how you can help your neighborhood/city to fix bad lighting, and to learn more about tips for fixing lighting in your home.

Images from NASA (public domain).