Night Lights

There’s a dark side to artificial lighting.
aerial of view of sacramento showing lights
Aerial view of Sacramento

Sacramento Magazine’s sustainability-column staff—all the researchers, writers, editors, interns, tech experts and retired annuitants who make the magic happen—recently had a problem. The city of Sacramento had replaced a streetlight out front, and the new light was so potent that the staff had to tuck a thick blanket over the big window’s curtain rod in the front room, which even with drapes fully employed was overpowered by artificial brightness.

The staff and his wife spoke with a friendly engineer in the city’s utilities department, and within a day a shield was installed inside the streetlight lamp, the effect of which was transformative. No longer was the front of the house lit up like a football stadium on Monday night TV.

We bring this up as (a) a salute to Sacramento city responsiveness, and (b) an introduction to this month’s topic: light pollution.

What is light pollution, you ask? Here with the answer is the International Dark-Sky Association.

“Light pollution is a side effect of industrial civilization,” the IDA explains. “Its sources include building exterior and interior lighting, advertising, commercial properties, offices, factories, streetlights and illuminated sporting venues.

“The fact is that much outdoor lighting used at night is inefficient, overly bright, poorly targeted, improperly shielded and, in many cases, completely unnecessary. This light, and the electricity used to create it, is being wasted by spilling it into the sky, rather than focusing it on to the actual objects and areas that people want illuminated.”

The IDA elaborates that light pollution can be subcategorized into four effects: glare (“excessive brightness that causes visual discomfort”), skyglow (“brightening of the night sky over inhabited areas), light trespass (“light falling where it is not intended or needed”) and clutter (“bright, confusing and excessive groupings of light sources”).

The National Geographic Society agrees that light pollution is a global problem, pointing out that 99 percent of Americans and Europeans reside in areas under skyglow (created by “electric lights of cars, streetlamps, offices, factories, outdoor advertising and buildings”). For humans, that glow can compromise sleep patterns and makes stargazing about as effective as listening to a lap cat purr while the neighbor is blasting away with a gas powered leaf blower. For animals, the consequences can be more dire:

“Because of light pollution, sea turtles and birds guided by moonlight during migration get confused, lose their way, and often die,” National Geographic reports. “Large numbers of insects, a primary food source for birds and other animals, are drawn to artificial lights and are instantly killed upon contact with light sources. Birds are also affected by this, and many cities have adopted a “Lights Out” program to turn off building lights during bird migration.”

If the presence of lighting is excessive, and lights operate on energy, it’s elementary to conclude that light pollution wastes energy. The IDA speculates that 30 percent of all outdoor lighting in the United States is pointless. “That adds up to $3.3 billion and the release of 21 million tons of carbon dioxide per year! To offset all that carbon dioxide, we’d have to plant 875 million trees annually.”

There are places on the planet that are mostly dark (Siberia, anyone?), and cities such as Flagstaff, Arizona, that are taking concrete steps to reduce light pollution. The IDA can point you toward these types of success stories.

The sustainability staff and its two housemates enjoyed dark skies at a few places last summer, including on Mount Wheeler in Great Basin National Park, in Nevada near the Utah border. Being able to see the Milky Way with the naked eye is an amazing experience, one that could be shared more widely should we become more enlightened about the pitfalls of artificial lighting.