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News / Life / Clark County Life

Darkness matters: Light pollution of night skies hurts people, animals in Southwest Washington

By Scott Hewitt, Columbian staff writer
Published: April 18, 2023, 6:03am
3 Photos
Light pollution from Goldendale floods the sky on a cloudy night at Goldendale Observatory State Park in 2014.
Light pollution from Goldendale floods the sky on a cloudy night at Goldendale Observatory State Park in 2014. (Associated Press files) Photo Gallery

We usually see light in a positive light. It cheers up gloom. It clarifies our way. It’s the Bible’s opening metaphor for all of creation.

Light is a genuinely problematic form of pollution, according to the International Dark-Sky Association, also known as IDA. Eighty percent of the world’s population — and an incredible 99 percent of Americans — live under an artificially glowing sky that blocks some, most or even all of the stars, according to IDA.

Saving the stars is one reason why IDA, an organization started by astronomers in the 1980s, now boasts 200,000 members and supporters in 61 countries around the globe. Environmental protection, wildlife conservation and human health are other reasons.

“Dark skies have gone from the niche concern of a handful of astronomers in the 1970s to an important area of research and study for many scientists,” said Bob Yoesle. The former Clark County amateur astronomer moved east years ago to Goldendale, in part for the great sky viewing and the big telescope housed at Goldendale Observatory State Park.

Dark Skies

Five principles for responsible outdoor lighting from the International Dark-Sky Association:

  • Useful. Before installing or replacing a light, ask yourself, is it needed? Does it have a clear purpose? Consider its impact on wildlife and the environment.​ Consider reflective paints for curbs and steps instead of outdoor lighting.
  • Point downward. Stick with “fully shielded” light fixtures that don’t allow any sideways leakage. Target the light carefully.
  • Low intensity. How bright do you really need? Don’t recreate sunshine at night, especially outdoors. Reflected light on asphalt and other urban surfaces contribute mightily to light pollution.
  • Color. Use warm colors where possible. So-called “warm white” light bulbs produce an amber-yellow tone that’s easier on the eyes and less impactful to the environment than harsher, brighter “blue-white” lights that cause most light pollution. A color temperature of 2700 Kelvin or less is ideal.
  • Control. Turn off lights when not in use. Incorporate timers or motion sensors. “Light where you need it, when you need it, in the amount you need, and no more,” the International Dark-Sky Association says.

Every April when the moon is “new” — that is, invisible — and nighttime conditions are at their darkest, the IDA sponsors International Dark Sky Week, an event started by a Virginia high school student named Jennifer Barlow. Dark Sky Week is an effort to promote, celebrate and protect the beauty of the night in an increasingly lit-up world. This year’s dates are April 15-22.

Dedicated dark sky lovers will travel to Oregon’s Prineville Reservoir State Park, east of Bend, for an April 22 dark sky extravaganza. Known for its awesome stargazing and designated an official Dark Sky Park by the IDA, Prineville Reservoir will host daytime festivities including a dark-sky talk and solar viewing by telescope, as well as a dark-sky telescope session at night. (Contact Oregon State Parks for more information.)


The spread of artificial outdoor lighting and light pollution over the past couple of centuries has disrupted wildlife and the environment, watchdogs like Yoesle say.

“Excessive lighting at night is not healthy for the environment or for biological systems that, for millions of years, evolved with natural day-night cycles,” he said.

Better lighting technology has hastened the problem. Incandescent light bulbs, which first appeared in the mid-1800s, emit amber and yellow hues — the warm colors of sunrise and sunset — that have long wavelengths that don’t diffuse into the sky. Incandescent bulbs aren’t major light-pollution culprits.

LED lights, however, are. They have become more common, especially as outdoor street and advertising lamps and car headlamps. LEDs emit a broader and brighter spectrum. They emphasize intense blue-white light that has a short wavelength that diffuses easily into the sky. That’s why the daytime sky naturally looks blue.

If you’ve ever gazed south toward Portland at night and noticed a vague, hazy shine hovering there, what you’re seeing is the widespread spillover of city lights up into the sky. Scientists call that skyglow.

“LEDs are very efficient. They produce a lot more light and almost no heat,” Yoesle said. “A lot of cities jumped on the LED bandwagon and put in horrendous, bright LED lights that recreate daylight at night.”

Trapped by light

Many migrating birds fly at night, guided by starlight. Many reptiles and other critters are also active at night. But many of their routines and activities are delayed, disturbed, confused or completely stopped when night is unnaturally bright. Light can disrupt birds’ circadian rhythms, impacting the timing of migration and other seasonal behaviors. Migration that goes wrong can leave birds prone to exhaustion and predation.

Bright or reflected light can attract, repel or otherwise disorient birds. Birds easily mistake shiny or transparent surfaces — like windows — for more open sky.

“Skyglow drowns out the stars, confusing (birds) and luring them into urban areas,” the Portland chapter of bird-conservation nonprofit Audubon says. “Once trapped in the windowed maze of the city, birds either hit buildings directly or circle them until they collapse from exhaustion.”

An estimated 1 billion birds die annually due to direct collisions with illuminated buildings, towers and other structures in the U.S., according to Audubon. One week in 2017, nearly 400 passerines were caught by floodlights illuminating a 32-story skyscraper in Galveston, Texas, and died in window collisions. After that, the American National Insurance Company elected to leave its floodlights off, Audubon reported.

“Audubon has become a big proponent of dark skies,” Yoesle said.

Many Audubon chapters, including the one in Portland, are promoting a program called Lights Out. While that can encompass everything from lobbying for light-limiting legislation to collecting collision data, Lights Out’s main thrust is simply encouraging people to voluntarily turn off unnecessary lights at night.

Such a simple solution to such a deadly problem, Yoesle said. In Chicago, researchers documented that 20,000 birds collided with a single lit-up skyscraper across 20 years. When unnecessary lights were turned off, bird deaths at that building declined by more than 80 percent.

Blues in the night

Bright light at night can disrupt people’s circadian rhythms, too. That may be one reason why one-third of all Americans report sleep problems like insomnia, according to the Centers for Disease Control and Prevention.

“In our hormonal system, melatonin is what helps you fall asleep. Melatonin production is spurred by the sun going down,” Yoesle said. “Blue light stimulates cortisol production. That’s the hormone that helps you wake up.”

Bright light in the morning can help you feel awake, but bright light at night may do the same. If you struggle with insomnia, avoid bright light at night and reset your screens to “night light” or “blue light filter” settings.


The sky’s darkness has long been measured by orbiting satellites looking down at light emitted or reflected upward, Yoesle said. Resulting data suggested that light pollution has been growing by approximately 2 percent per year.

But a newer approach, based on eyewitness observation, shows much faster change. A study published in January in the journal Science relied on citizen scientists who signed up with a project called Globe at Night. They went outside on moonless nights during specified weeks of the year and scanned the sky for certain constellations that should be visible. Participants forwarded their observations about overall darkness (and weather conditions), level of skyglow and the faintest constellation star they can see.

Drawing from the reports of more than 51,000 citizen scientists, the new Globe at Night study found that the average night sky grew 9.6 percent brighter each year from 2011 to 2022. That’s equivalent to doubling the sky’s overall brightness every eight years.

Can you see Leo the Lion? That’s the target constellation for participants in the Northern Hemisphere this week. In May, Leo will be joined by Bootes the Plowman. Neither is the most familiar constellation, but the Globe at Night webpage provides directions for tracking them down.

Small planet

Yoesle said he’ll never forget his first clear view of the Milky Way as a child visiting Mount Lassen in Northern California.

“It was literally a religious experience. I hate to sound philosophical, but it was a spiritual thing,” he said.

The Clark County resident moved to Goldendale in retirement, motivated in part by a storied 24.5-inch telescope built by Clark County amateurs that was stored at Clark College and eventually moved to Goldendale, where it came to anchor a new state park.

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Yoesle lobbied the International Dark-Sky Association to designate Goldendale Observatory State Park as an official Dark Sky Park. The designation is for parks with exceptional starry nights and a protected nocturnal environment. The site won that designation in 2010, but lost it a few years later as the town of Goldendale grew and brightened, much to Yoesle’s disappointment and frustration.

“We are on a very small planet in an infinite universe, and we’ve lost connection with that,” Yoesle said. “It’s an unbelievably magical universe, but when kids can no longer grow up seeing the stars, seeing the Milky Way, they’ve lost that magic.”