By David Oonk

July 12, 2021

The word pollution may trigger images of soot-emitting factories, high areas of congestion on highways, plastic bottles and litter, and chemical spills into our waterways. More unlikely, however, is to immediately associate light as a source of pollution. But light pollution is indeed a form of contamination, and one that has gotten worse over the years. Recognizing the problem, many areas of Colorado and the rest of the nation have taken action to reduce light pollution or even receive a designation as dark-sky reserves and communities. 

What’s Up with Light Pollution?

Keeping the lights on—or, in the case of cities, many bright lights on—throughout the night may seem innocuous, but the truth is that excessive light causes light pollution. Light pollution can cause biological harm, can lead to light trespass and nuisance claims, and can even detract from cultural experiences and histories. 

Light pollution can have biological consequences for both flora and fauna, including human life. According to the International Dark-Sky Association (IDA), artificial light can have negative—and even deadly—effects on amphibians, mammals, birds, and plants. Today, especially near cities, skies are hundreds or thousands of times brighter than they were two centuries ago. Nighttime croaking is a breeding ritual amongst frogs and amphibians, which is interrupted by artificial light; birds that hunt at night do so by moonlight or starlight, and artificial lights can lead them off course; declining insect populations, which could be a result of artificial lights fatally attracting insects, can hurt other species that rely on insects for food; and, of course, humans’ circadian rhythms are affected by light. 

Light pollution doesn’t just have biological effects, but cultural ones, too. Enjoying starry nights in a dark environment can have heritage, cultural, and public enjoyment benefits (as well as scientific ones!). Dark night skies may also be part of a cultural landscape and landscape history, explains Spencer Burke, a park ranger at Mesa Verde National Park. “The night skies are part of the cultural landscape of this place. You can seek the same night sky as the Ancestral Pueblo people saw when they lived here, surrounded by the same trees and animals.” Dark skies can also attract tourism and help to support local economies as such, too. 

What Is a Dark-Sky Reserve?

Recognizing the harm of light pollution and the benefits of dark skies, many areas throughout the nation have started the process of becoming Dark-Sky Reserves (sometimes called dark-sky preserves). As defined by IDA, a dark-sky reserve “is “a public or private land possessing an exceptional or distinguished quality of starry nights and nocturnal environment that is specifically protected for its scientific, natural, educational, cultural, heritage and/or public enjoyment.”

In order to earn the designation as a dark-sky reserve, there must be natural darkness, a community commitment to preserving air and sky quality, and a specific unpolluted sky quality. There are light pollution restrictions in dark-sky reserves, and one must be able to see the Milky Way. Similar to a reserve is a dark-sky community—“ a town, city, municipality or other legally organized community that has shown exceptional dedication to the preservation of the night sky through the implementation and enforcement of a quality outdoor lighting ordinance, dark sky education and citizen support of dark skies.” 

For most inhabited parts of the world, transitioning to a dark-sky haven requires engaging residents and getting them to agree to reduce their outdoor light usage, measuring light levels, and rethinking public light fixtures. 

Saving Dark Skies in Colorado

Recently, four more Colorado towns have been certified as dark-sky-friendly places. The name of one of the towns has yet to be revealed; the others are Crestone, Nucla, and Naturita. Silver Cliff, West Cliffe, and Norwood are also recognized dark-sky communities. Creede, Colorado is in the process of becoming a dark-sky community. The importance of dark skies is being acknowledged at the state level, too. Colorado maintains an “experience the night” campaign, and Governor Jared Polis has even mulled over the idea of designing June as the official dark-sky month.

While turning out the lights may not solve all of our environmental woes, most people can agree that there’s something magical about looking up in the bright, unadulterated night sky. Reducing light pollution may just be an environmental goal that we can all agree on.