Photos: NASA Earth Observatory
Lights Out!
You may be surprised to hear that light can be a form of pollution. In fact, both plants and animals have adapted to the earth’s daily, monthly, and seasonal rhythms of light and dark. Artificial lighting disrupts those rhythms impacting the health of many species, including our own.
Fortunately, addressing light pollution is a win-win. We can help the planet, save money on utility bills, reduce our carbon footprint, improve our own health, and enjoy clearer views of stars and planets. Reduced nighttime lighting does not need to be at the expense of safety. Research has shown that extra lighting has little impact on crime rates.
Impact on Wildlife
Cycles of light and dark govern animal and plant behavior in many ways, including sleep patterns, mating, migration, hunting, hibernation, flowering, budding, and leaf drop. For example, light from stars and the moon is critical to the migration of billions of birds ranging from hummingbirds to geese. Skyglow from cities and towns can confuse birds, causing them to circle urban areas where they risk danger from exhaustion and window strikes.
Impact on Human Health
According to the American Medical Association, “brighter residential nighttime lighting is associated with reduced sleep times, dissatisfaction with sleep quality, excessive sleepiness, impaired daytime functioning and obesity.” This is especially true for blue-rich LED lighting. Use of the warm, yellow-rich end of the spectrum and installation of proper shielding is critical when using energy-efficient LED lights.
Lights Out: Philadelphia Darkens Its Skyline to Protect Migrating Birds
Source: International Dark Sky Week
How You Can Help
You make an important contribution when you reduce nighttime lighting. This is especially critical during the spring and fall migration periods.
Eliminate unneeded lighting
Use motion-sensitive bulbs for exterior lighting
Use smart plugs or other timing devices to turn decorative lighting off at bedtime
Use energy-efficient LED bulbs, but only those that operate in the warm, yellow end of the spectrum
Make sure exterior lights are properly shielded so they illuminate only these areas needed. Avoid bare light bulbs
Business owners are well positioned to help by:
Turning off ornamental and rooftop lighting
Extinguishing interior lighting on upper floors
Scheduling maintenance and cleaning during daytime hours
Using downward rather than upward pointing sign lighting
Research on Lighting & Safety
Many years of research on the relationship between lighting and safety, both in terms of crime and traffic accidents, have proved inconclusive. In fact,
The Chicago Alley Lighting Project found a 21% increase in crime associated with increased lighting frequency and wattage.
A review of literature by the Pacific Gas and Electric Company found that “None of the papers reviewed presents sufficient evidence to demonstrate a causal link between night-time lighting and crime.”
A thirteen-year study in the UK found “little evidence of harmful effects of switch off, part-night lighting, dimming, or changes to white light/LEDs on road collisions or crime in England and Wales.”
Additional Resources
The International Dark-Sky Association has great resources, including information on:
How to Bring Lights Out to a City Near You
Audubon chapters across the U.S. have been instrumental in convincing cities to turn their lights out for migrating birds.
We Finally Know How Bright Lights Affect Birds Flying at Night
A new study, based at New York City's 9/11 tribute, shows that artificial lights lure birds from their migratory routes.
Lights Out for the Texas Skyscraper That Caused Hundreds of Songbird Deaths
With input from local wildlife groups and birders, the owners are shutting down the lights and turning up the dialogue around bird-friendly practices.