SALT LAKE CITY (ABC4) — International Dark Sky Week is a week dedicated to raising awareness of the harms of light pollution, celebrated worldwide from April 15 through April 22.

According to the International Dark-Sky Association (IDA), light pollution is any artificial light that is unnecessary. And it is a pollutant that has harmful consequences. It is increasing at two times the rate of population growth, and currently, approximately 83% of the global population lives under a light-polluted sky.

The Effects of Light Pollution

1. It disrupts wildlife

Plants and animals have depended on Earth’s cycle of light and dark, but according to research done by IDA, humans have disrupted this cycle by lighting up the night. According to IDA, artificial lights disrupt the world’s ecosystems. Nocturnal animals sleep during the day and are active at night, but due to light pollution, their cycles are altered by the pollution turning night into day.

“Predators use light to hunt, and prey species use darkness as cover,” research scientist Christopher Kyba said. “The introduction of artificial light probably represents the most drastic change human beings have made to their environment.”

According to IDA, glare from artificial lights can also impact amphibians in wetland habitats, such as frogs and toads, whose nighttime croaking is part of the breeding ritual. Artificial lights disrupt this nocturnal activity and interfere with reproduction, which reduces populations, IDA said.

Artificial lighting can also lead to the deaths of baby sea turtles, IDA stated. They said that because sea turtles hatch at night on the beach, but live in the ocean, they find the sea by detecting the bright horizon over the ocean. But due to artificial lighting, millions of hatchlings follow the artificial lights instead of the sun, and end up dying as a result.

Light pollution also has devastating effects on many bird species, IDA claimed. They said birds that migrate or hunt at night will use the moon and stars to navigate, but artificial light can cause them to get lost and wander toward dangerous landscapes in cities. Every year, millions of birds die colliding with illuminated buildings and towers, IDA stated.

2. It impacts human health

“Many species (including humans) need darkness to survive and thrive,” the American Medical Association Council on Science and Public Health said.

Humans adhere to a circadian rhythm, using a sleep and wake pattern governed by the day and night cycle. According to IDA, artificial light at night can disrupt that cycle. Humans produce the hormone melatonin to induce sleep, boost the immune system, and more. Nighttime exposure to artificial light reportedly suppresses melatonin production.

IDA suggested limited exposure to artificial light at night, such as computer screens, televisions, and other electronic displays. They also recommended adapting your electronic screen to warm light at night.

3. It wastes money and energy

Artificial lighting that emits too much light or shines when and where it is not needed is wasteful, IDA reported. In the U.S., outdoor lighting uses about 120 terawatt-hours of energy, which IDA said is mostly used to illuminate streets and parking lots.

They recommended installing quality outdoor lighting, which could cut energy use and carbon emissions. IDA also recommended using outdoor lighting that is fully shielded to direct light where it is needed, instead of into the sky. And unnecessary indoor lighting, such as empty office buildings at night, should be turned off.

Watch a clip from a documentary, found on IDA’s website, to learn how to reduce light pollution and conserve energy.

4. It blocks our view of the universe

Van Gogh painted “Starry Night” in Saint Rémy, France in 1889. The Milky Way can reportedly no longer be seen in that area due to light pollution. The IDA website said, “If he were alive today, would he still be inspired to paint “Starry Night?”

According to IDA, experiencing the night sky provides perspective and inspiration, leading us to reflect on our place in the universe. Without the natural night sky, the human race could not have navigated the globe, walked on the moon, or made discoveries in astronomy.

The IDA will recognize communities, parks, reserves, and sanctuaries that have “excellent stewardship of the night sky.” The designations are based on strict outdoor lighting standards, as well as innovative community outreach. You can read more about the certifications here, and view an interactive map of places that are certified.

How to Celebrate International Dark Sky Week

There are eight actions that the IDA recommended for celebrating International Dark Sky Week:

  1. Be a community scientist.
  2. Inventory your home lighting.
  3. Host a night walk.
    • You can take a Dark City Walk, which is a guided walking tour that demonstrates how the lighting we add to our cities impacts the way we use them and the environment at large. For a how-to-guide, click here.
  4. Become a Dark Sky Advocate.
  5. Partner with other organizations.
    • You can connect with a partner organization and tell them about the importance of reducing light pollution, or host an event with them to introduce new audiences to the value of dark skies. Click here for more information.
  6. Participate in a scavenger hunt!
    • Take part in the International Dark Sky Week scavenger hunt. You will be tasked with finding as many items on the international list as you can during the week. If you find them all, the IDA will send you stickers. The list is available here. To claim your stickers, click here.
  7. Receive an official proclamation.
    • During Dark Sky Week, you can get Dark Sky Week to be officially proclaimed, or recognized, by a local government agency. To read more about how to do this, click here.
  8. Write a letter to your local news station.
    • Sending information about important events to your local news stations is a great way to raise awareness about issues.