By. Christian Baran

Do you remember the last time you saw a night sky filled with stars? Not just a couple littered throughout a hazy sky, but the glittering sea of diamonds set against an inky black expanse that we now only associate with extremely remote areas or planetariums? I’m going to guess that, for most of you, it’s been awhile. 

This is of no fault of our own. For almost a century and a half, our world has been soaked with artificial light so thoroughly that many of us don’t know anything different. In 1994, when power went down in Los Angeles following a devastating earthquake, emergency services fielded dozens of calls from residents worried about a “giant, silvery cloud” in the sky. It was the Milky Way.

Our starless skies are a direct result of light pollution, an insidious form of pollution that goes unnoticed by most. Although much artificial light is helpful, even necessary, it can quickly become a pollutant when it turns excessive or inefficient. And light pollution doesn’t just spoil the night sky. It also wreaks havoc on our climate and the ecology of our world.

Unshielded streetlights diluting the skies above may seem far removed from an issue like climate change. But think about the sources of that light. Electricity production is the second largest emitter of greenhouse gases in the United States, just barely lagging behind transportation. Almost 20% of that production goes toward powering our lights. That gas station you pass on your drive home isn’t just spewing artificial light into the night sky. It’s also letting greenhouse gas production go to waste. 

But wait. Artificial light isn’t all bad. We need it to see at home, illuminate our offices and feel safe walking around our cities. How much actually qualifies as light pollution? According to the International Dark Sky Association (IDA), the number is shockingly high. Almost 30% of all outdoor light goes to waste, escaping into the sky from unshielded or improperly placed bulbs. This wasted light has devastating impacts for our climate, causing about 21 million tons of carbon emissions per year.  That’s equivalent to over the emissions of over 4.5 million cars being driven for one year. It’s a number we can’t afford in a climate crisis. Unfortunately, light pollution’s trail of destruction doesn’t stop there. 

Light pollution’s reach extends to ecological systems around the world. Most animals, including 70% of mammals, are nocturnal. They’ve adapted over millions of years to forage, socialize and hunt in the dark. Even slight changes in lighting patterns can set off chain reactions in delicate ecosystems, disorienting food chains and mating cycles. Human society has brought a bit more than slight change over the past 200 years, resulting in drastic alterations to ecosystems everywhere. One poignant example involves sea turtle hatchlings. 

Although sea turtles spend the majority of their lives in the ocean, most of them hatch from nests on beaches. Hatchlings have evolved to head for the brightest spot around once they’ve broken free of their eggs, which has historically been the ocean reflecting moon and star light. However, as society has congregated around the coastlines, building cities and other bright developments, it’s had the inadvertent effect of confusing sea turtle hatchlings. Disoriented, baby sea turtles turn their backs on the ocean and crawl instead toward bright lights further inland to be crushed by a car or die of dehydration in a concrete jungle. In Florida alone, light pollution is responsible for millions of sea turtle deaths each year.  

Luckily, light pollution prevention is simple, if not necessarily easy. Outdoor lighting should be fully shielded and directed downward. If people would focus their lighting on where they needed to see, rather than into the sky, light pollution would for the most part cease to be an issue. As a rule, then, no light should be emitted above the horizontal plane. There’s simply no need in most cases, and it’s easily accomplished by installing shields. 

Other solutions are equally as intuitive. Outdoor lighting should only be turned on when needed. Commercial buildings that are unattended after the workday can be retrofitted with motion sensors and timers to cut costs and prevent light pollution. Cost-effective LED lights are good options for those on a budget as long as they avoid blue-light bulbs, which are more damaging to the night sky than light with lower color temperatures. Solutions like these are easy to implement; the small costs are well worth the ability to see our night skies in all of their primordial glory.

As long as humanity has existed, we’ve been able to look up each night and see a dazzling array of stars lighting up the night. The heavens have served as inspiration for countless pieces of art, literature and folklore since our Ice Age ancestors began scribbling star maps on walls. Now, 99% of people living in the United States or Europe are unable to see the Milky Way due to light pollution. Light pollution is slowly killing our planet and taking our night sky heritage hostage. For the sake of our planet and its magnificent view, please take action on light pollution and support local organizations. If you’re interested in getting involved in community action, check out the Facebook page for the Washington, DC Chapter of the IDA. If you’re located elsewhere, find a nearby IDA chapter here.

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