When was the last time you saw the Milky Way? Have your children ever seen the Milky Way?
Recently, when I took my astronomy class to the planetarium, one student asked, "What are the clouds in the sky?" He was referring to the Milky Way, stretching across the sky — something he had never seen, though he grew up in Hawaii.
For the first time in our society, an entire generation is growing up without having seen the Milky Way, and never having the opportunity to gaze out into the vastness of space to consider their place in the universe.
Decades of poorly designed lighting by the City & County, the state, companies and private individuals have robbed Oahu’s residents of the ability to see the night sky. Millions of dollars of energy are being wasted on Oahu each year lighting up the night sky. In contrast, the night sky over Hawaii island and Maui have been protected by careful lighting ordinances designed to protect the astronomical observatories there. And Kauai has some of the world’s best lighting due to the impact that lighting has on endangered birds.
Lighting is currently undergoing a revolution. The 2014 Nobel Prize in Physics was awarded for the invention of efficient blue-light-emitting diodes (LEDs). A phosphor is used to create white LED light. The light from LEDs is easier to direct, and this allows areas such as roadways to be illuminated using less total light, saving energy.
But one of the problems with LEDs is that they produce much more blue light than traditional forms of lighting such as high-pressure sodium (the orange-colored streetlights common on Oahu). Blue light is easily scattered by air molecules, so adding a lot of it at night will further diminish our ability to see the night sky. More worrisome is that blue light suppresses production of melatonin, the natural hormone that controls circadian rhythm — the sleep cycle. Suppressed melatonin levels have been shown to increase the growth rate of human cancer cells. And excess blue light causes the human iris to contract, which may reduce visibility.
The City and County of Honolulu has issued a request for proposals to replace all city streetlights on Oahu. It has specified blue-rich 4000K LEDs that are similar in color to the blue-rich car headlights that many of us have grown to hate. Islandwide installation of these "zombie lights," which are a strong source of glare, would render much of Oahu with a harsh sterile ambience at night.
The city should learn from the experience of Davis, Calif., where blue-rich white LEDs streetlights were installed. Residents complained vociferously, and city officials reacted appropriately. The blue-rich LEDs were replaced by much-warmer 2700K LEDs that have a color similar to typical home night lighting and conventional car headlights, and create a much more inviting ambience.
Streetlights are one of the major polluters of the night sky. Poorly designed light fixtures spray a lot of light directly upward. Replacing them is a wonderful opportunity to reverse decades of poor lighting practices, by specifying light fixtures that are properly shielded and send light downward where it is needed.
By specifying blue-rich lighting, the city is squandering this one-time opportunity to undo the damage that we have all wrongly accepted as part of urban life.
Replacing Oahu’s streetlights is a wonderful opportunity to restore our view of the night sky, to replace light trespass from streetlights into our homes, and to save energy.
The city should cancel the current request for proposals for 4000K LED streetlights — the deadline is Tuesday — and revise it to require warmer-colored, properly shielded streetlights. This change would be cost-neutral: Warmer-colored LED streetlights that exceed the energy efficiency specified in the request for proposals are already available.
Making the change now would avoid a costly change order in the future.
