Preserving the Night: Light Pollution and the Threat to Wildlife, People and Culture

The Milky Way as seen from Kissemmee Prarie Preserve. Photo courtesy of Florida State Parks

The Ancient Migration

Each autumn, Florida prepares for familiar seasonal changes—holiday celebrations, cooler evenings, and the arrival of “snowbirds” from the north. But another migration, one far older than Florida itself, is also underway: the annual fall journey of millions of birds. Roughly 60 percent of bird species are migratory, many traveling at night. Birds use a combination of sensitivity to the Earth’s magnetic field, instinctual landmark recognition, and celestial navigation.

Unfortunately, light pollution disrupts two of these natural systems. Artificial lights draw birds into urban areas, where they often become trapped in a cycle of confusion—flying in circles until exhausted, colliding with buildings, or falling prey to predators. The toll is staggering: an estimated 600 million birds die each year from building strikes alone, and nearly three-fifths of migratory bird species are now at risk of extinction.

Ripple Effects Across Ecosystems

The effects go far beyond birds. Sea turtles are notoriously sensitive to beach lighting. Hatchlings crawl toward the brightest horizon, which should be the moonlit ocean but is often the glow of condominiums and streets. The most recent nesting season saw high numbers of “false crawls,” when female turtles abandoned nesting attempts due to lights and human activity.

Volunteers with Coastal Connections Inc. examine "false crawl" tracks. Photo by Joe Rimkus

Kendra (Cope) Bergman is Founder and Executive Director of Coastal Connections, Inc., a leading non-profit organization in Vero Beach dedicated to educating and involving the community in sea turtle conservation efforts. Her organization helped beach-facing businesses and homeowners to embrace, adopt and implement turtle-friendly lighting practices in Indian River County. She explains further how artificial light affects sea turtles:

"Light is a threat many don't associate with sea turtles, however, it is one of the leading causes in hatchling disorientation and death before they even make their way to the ocean. Light can also cause nesting sea turtles to false crawl (turn around without nesting) and find a darker, safer spot to lay her eggs. Sea turtles can see, and are attracted to, the color white and other short wavelengths of light, which is why we have lighting ordinances in place across Florida during the sea turtle nesting season (March 1 - October 31). Long wavelengths of light, such as red or amber, are not as attractive to sea turtles, minimizing negative impacts, and thus are considered "sea turtle friendly." However, the most sea turtle-friendly lighting is no lights at all. It's recommended to turn off all outside lights if not in use, close curtains after dark, and keep any outside lights long in wavelength, low to the ground, and shielded to prevent direct impact on sea turtles and other wildlife."

Insects—already declining due to habitat loss and pesticides—are further threatened by light that disrupts their natural cycles. Pollinators are vanishing, fireflies may only be a generation from disappearing completely as bioluminescent species cannot tolerate additional artificial light. Even corals and plankton in marine environments respond negatively to light pollution, with blue wavelengths penetrating more than 100 meters into the ocean and altering reproductive timing.

The Human Impact

For humans, the impacts are both cultural and biological. Scientists estimate that 90 percent of North Americans and Europeans now live under light-polluted skies, with 80 percent unable to see the Milky Way at all. As Jon U. Bell, Associate Professor of Astronomy and Hallstrom Planetarium Director at Indian River State College, explains:

“There are so many things that occupy our busy lives that we often forget to look up at the beautiful night sky. And then at last when we do look up, and find that night sky turned gray and bereft of stars, we suddenly realize that we have lost something of great value. In the planetarium theater we can allow folks to see how the night sky should look, without the streetlights. And we point out those seemingly countless stars and we name them. So that when at last you have a chance to see the real sky, on a camping trip away from cities perhaps, or on a Florida beach overlooking the great Atlantic Ocean at night, you can make that connection with the universe once more and count the friendly stars.”

The beauty of the night sky is only part of the story. Artificial lighting, particularly the blue-rich light emitted by many LEDs, disrupts circadian rhythms in humans. Overexposure to blue light suppresses melatonin production, which regulates sleep, immune response, and mental health. Screen time from phones, televisions, and computers only adds to this problem, creating what many researchers consider a public health issue.

LEDs and the Growth of Skyglow

Ironically, newer LED technology—while more energy-efficient—hasn’t reduced energy consumption. Because lights are cheaper to operate, society has simply installed more of them. Skyglow, the diffuse haze of light over urban areas, has increased nearly 10 percent per year since 2012.

Astro photographer Rob Martin, whose photo is featured on the cover of this issue, describes LED lighting as having no natural enemies because of its emission of short-wavelength blue light.

“A hundred years ago, the night sky was lit with thousands of stars, now you are lucky to see a few hundred in suburban areas, and much fewer in heavily lit cities. As an astrophotographer, the bane of my existence are the box store parking lots, neighbor's motion flood lights and streetlights, all of which are broad spectrum LED lights that are impossible to filter out due to the huge swath of the visible spectrum they occupy.”

And brightness does not always equal safety. Glare from over-lighting can reduce visibility and create a false sense of security, masking potential hazards.

Solutions Already Working

Despite these challenges, solutions exist. Across the U.S., cities like Dallas, San Antonio, Chicago, and Philadelphia have adopted “Lights Out” programs during peak migration seasons. These initiatives encourage businesses and residents to reduce unnecessary outdoor lighting at night. The results are clear: some cities report up to 25 percent fewer bird deaths.

Practical steps include turning off lights in unoccupied buildings, dimming or shutting off signage after business hours, lowering street lighting after 11 p.m., and using timers or motion sensors for security lights. Homeowners can help by choosing warmer-colored, lower-lumen bulbs, installing shielded fixtures, and closing curtains to block indoor light spill.

These practices align with the Five Principles of Responsible Outdoor Lighting, developed jointly by DarkSky International and the Illuminating Engineering Society:

1) Use light only when needed

2) Use only the amount needed

3) Aim light where it’s needed

4) Use warmer-colored light

5) Control lights with timers or sensors

The Role of Advocacy

Unlike air, water, or soil pollution, light pollution has no residual effects. Turn off the light, and the pollution disappears. This makes it one of the simplest environmental issues to address—yet also one of the most overlooked.

DarkSky International, formerly the International Dark Sky Association, has been at the forefront of this movement for decades. Supported by over 3,000 volunteer advocates worldwide, including the Treasure Coast Astronomical Society, DarkSky promotes responsible lighting, certifies DarkSky places, and educates communities about the ecological, cultural, and health impacts of light pollution. The goal is not to eliminate lighting altogether, but to ensure it is used wisely, preserving safety while protecting the natural night.

Reclaiming the Night

From migratory birds to sea turtles, from insects to people, the night sky touches all species. Protecting it is both a practical necessity and a cultural responsibility. As Jon Bell reminds us, looking up at a star-filled sky reconnects us with the universe and with one another. By rethinking how we light our nights, we help ensure that future generations will not only inherit healthy ecosystems but also the wonder of counting the “friendly stars.”