Twinkling little stars are getting harder to see because human-caused light pollution makes the night sky glow brighter each year. Excessive, poorly designed lighting that trespasses into the nocturnal world changes the predictable day and night cycle of life, consumes and wastes energy, contributes to climate chaos, and steals the wonder and beauty of the night sky. Damage to biological and ecological rhythms cause widespread, harmful impacts on health and safety for humans and wildlife.
Countless wildlife species that work the dusk and dawn or graveyard shifts need uninterrupted darkness to provide intricately timed cues that direct communication, orientation, reproduction, sleep, protection, and foraging.
The Pacific Flyway brings millions of migratory birds into Portland’s airspace at night during spring and fall. Most use celestial cues to navigate, but artificial lights lure birds into the maze of city lights, which causes confusion, exhaustion, and collisions with buildings. Research documents that 500 native species of birds are affected, and light pollution kills an estimated one billion birds each year in North America.
Furthermore, arthropods such as moths — their fate seamlessly interconnected with other creatures — perish rather than pollinating, breeding, and supplying bird food. Even the seasonal cycle of Portland’s trees — particularly those beneath streetlights or other lighting — is threatened, which in turn affects other organisms. Research has found that early bud break and leaf development caused by incessant light will have a cascade effect on other organisms whose life cycles work in tandem with such plants, as well as the plants themselves.
The Bright Side
Although nights are getting brighter each year with increased development, it is reversible. And while it will take urban planners and elected local officials to create mandatory standards that minimize light pollution, we can each do our part at home. DarkSky Oregon, part of an alliance of 25 other US cities, and the Lights Out campaign ask Portland businesses and homeowners to help. Here’s how:
- Turn off unnecessary outdoor lights (including “decorative” landscape lighting) and install motion sensors that turn on only when needed.
- Use fixtures that aim light downward and are shielded to prevent glare and light scatter.
- Select low-intensity warm LEDs (under 3,000 Kelvins) that supply only the amount of light needed.
- Close draperies at night, especially during peak migration seasons (April to May and September to November).
- Visit tinyurl.com/yt9nsuh9 to request that PBOT add shields or re-angle streetlights that scatter too much light.
- Tell your friends!
For more information visit darkskyoregon.org or the Bird Alliance of Oregon’s Lights Out page at tinyurl.com/n3rzxzuz.
Safety Concerns?
Studies show that most home burglaries occur in broad daylight, and excessive lighting does not lessen crime. Artificial lights can make victims and property easier to see, as well as create much greater contrast and excessive glare, which increase the deep shadows that may actually assist crime and vandalism. To improve security, use motion-activated lights to surprise intruders (Source: darksky.org).
Beaumont-Wilshire resident Eileen Stark is an ecological landscape designer and author of Real Gardens Grow Natives: Design, Plant, & Enjoy a Healthy Northwest Garden.