More than 20 years ago, the state of Florida, scientists and technical advisors determined that the best way to protect sea turtles from harmful beachfront lighting was to lower fixture mounting heights, shield the light source, and use long wavelength lamps. Sea Turtle Conservancy (STC) has successfully used this strategy to retrofit hundreds of beachfront properties in Florida, and while wildlife friendly lighting directly reduces sea turtle disorientations, it also benefits humans.
After decades of research and successful conservation efforts, we now know that white, unshielded light is harmful to sea turtles and other wildlife. Short wavelength light, which contains all colors on the electromagnetic spectrum, disrupts the sea-finding ability of hatchling sea turtles and discourages nesting in adult females. Light pollution also negatively impacts the life cycles of birds, insects and other wildlife. Researchers are now beginning to understand the impacts of blue-rich light on humans, and in 2016, the American Medical Association (AMA) even published a warning to the public about the health impacts of white LED street lights, which are quickly replacing high- and low-pressure sodium lights of the past.
In comparison to conventional street lights, white LED street lights create stronger glare for drivers and impact our circadian rhythms five times greater than non-LED options. The AMA warning stated that blue-rich LED street lights suppress melatonin at night and are associated with “reduced sleep times, dissatisfaction with sleep quality, excessive sleepiness, impaired daytime functioning and obesity.”
To address this growing issue, inland communities can use LED streetlights that have a color temperature of 3,000 Kelvin, instead of the typical 4,000-5,000 Kelvin LED fixtures that are used for street light replacements. Lowering the color temperature of a fixture reduces the amount of blue-rich light, which is a practice that can also be achieved by using sea turtle friendly, long wavelength pole fixtures in coastal communities. Shielding and lowering fixtures also ensures that light doesn’t escape into the sky and reduces glare while driving.
These principles can also apply to the lighting on your home. While installing an intense white floodlight may provide an illusion of safety, unshielded lights create deep shadows and temporary blindness that may make it even more difficult to see potential intruders on your property. By lowering mounting heights, shielding fixtures and using long wavelength light, local communities and homeowners can have the best of both worlds by protecting wildlife and human health.
For information on how to encourage your local community to use wildlife friendly street lighting, visit the International Dark Sky Association at darksky.org. To find examples of wildlife friendly lighting to use, visit Beachfront Lighting.