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The State of Minnesota and Grand Portage Band of Lake Superior Chippewa proclaimed April 2-8, 2024 as International Dark Sky Week. Here are five things to know about light pollution at night

Apr 04, 2024 07:55AM ● By Content Editor
Photo: Jackson Hendry

By Laura Durenberger-Grunow - Boreal Community Media - April 4, 2024

International Dark Sky Week is a global initiative that celebrates the night sky by promoting dark sky exploration and building preservation awareness. 
This year, April 2-8 has been declared as 'International Dark Sky Week'. What's more, the State of Minnesota and the Grand Portage Band of Lake Superior Chippewa have proclaimed April 2-8, 2024 as International Dark Sky Week. 

 Image: Starry Sky North

  Image: Starry Sky North

Cook County and Grand Portage residents are well aware of the magical beauty a clear night sky brings. Visitors to the area are often blown aware by the vast number of stars and planets that can be seen with the naked eye, and of course, seeing the Milky Way. People travel from all over to get a glimpse - even sparking a newer form of tourism called 

 The Bortle Scale - Source: IDA tumblr

But that's not the case everywhere, and dark skies are at risk. 

Boreal Community Media spoke with Caroline Torkildson, a delegate of the International Dark Sky Association (IDA) and 
Starry Skies North, a local non-profit (and the Minnesota chapter of the  IDA) to learn more about light pollution at night, and ways we can help keep our skies dark. 

"Eighty percent of Americans and one-third of humanity can’t see the Milky Way," Torkildson shared. 

Organizations like Starry Skies North and the 
IDA are working to preserve darkness and educate others about the importance of reducing light pollution at night. 

In July 2020, the Boundary Waters Canoe Area Wilderness was named a 'Dark Sky Sanctuary by the IDA' - one of 13 such places in the entire world. It's also the largest site at 1,098,000 acres, according to the National Forest Service - Superior. Voyageur National Park was named a 'Dark Sky Park' around the same time. 

According to the 
IDA, a Dark Sky Sanctuary is “public or private land that has an exceptional or distinguished quality of starry nights and a nocturnal environment that is protected for its scientific, natural, or educational value, its cultural heritage and/or public enjoyment.”   

Looking beyond astrotourism and public enjoyment, there are impacts of brightening skies on human health and the ecosystems we live in. 

Here are five things to know about light pollution at night. 

More lights do not necessarily equal a safer space

It's common knowledge: the more streetlights and house lights we have turned on in a community, the safer it is. Right?

"We may feel safer, but the common bright, bluish, unshielded lights actually decrease safety. These lights cause glare and can be so bright that we can’t see in the shadows," Torkildson said. 

It's about quality, not quantity, she continues.

"Better lighting helps with safety. Timers, motion sensors, shielded lights, and warmer bulb temperatures (amber) all contribute to safety by reducing glare, and motion sensors turn on only when something is there, alerting us." 

Light bulb color and temperature

Turns out that bulb temperature and color are very important in preserving the dark sky. Even better, it's an easy solution that we can make in our everyday lives. 

Torkildson recommends replacing the typical blue LED bulbs with warmer-colored options.  

"All bulbs have a label, either on the package or on the bulb."

 Look for: 

  • ‘light appearance’ of warm white, 2700 K or lower (K means Kelvin and is a scale of temperature), 
  • ask for dark sky-approved options
  • look for 'wildlife-friendly' lighting

Here is an example of a label: 

The harmful effects of blue lights 

Excess lighting at night may not seem like a big deal, but there are risks to human health. 

Most of that comes in the form of blue light emitted from indoor and outdoor lighting. 

"One of the main health concerns is that indoor and outdoor blue light more adversely suppresses melatonin (a key ingredient that helps us sleep) at night than warmer bulb colors," Torkildson said.

Melatonin suppression can then affect our circadian rhythms, which can "increase risks for obesity, depression, sleep disorders, diabetes, breast, prostate and colon cancer,"
 she added.

Indoor and outdoor blue lighting is becoming such a concern to human health that in 2016, the American Medical Association recommended reducing exposure to blue light and adapting good outdoor lighting practices.

Torkildson shared that "it is estimated blue LEDs have five times more impact on circadian rhythms than the old sodium lights."

And it's not just human beings that are affected. Our ecosystems are also impacted. 

Ecosystem impacts

According to research scientist Christopher Kyba via the IDA, "For nocturnal animals, the introduction of artificial light probably represents the most drastic change human beings have made to their environment. Near cities, cloudy skies are now hundreds, or even thousands of times brighter than they were 200 years ago."

Unfortunately, the impacts on the ecosystems we live in (and rely on) are high. Tons of species rely on the darkness to survive, and the increase in artificial lighting at night is greatly impacting them. If you'd like to learn more, visit:

Ways we can help

Besides replacing blue light LED lightbulbs (indoors and out) with warm-colored ones, Torkildson shared other ways we can take action and reduce light pollution.

"The first thing I recommend people ask is: "Is your outdoor lighting necessary?"

Source: IDA

If the answer is yes, there are ways to minimize the impact. 

"You can use the lowest brightness necessary (watts), shield your outdoor lighting so the beams are more directed, and use motion sensors or timers,( they are also better for safety)," she suggested. 

 Theodore Roosevelt National Park via IDA 

According to the IDA, "35% of lighting is wasted due to unshielded or poorly aimed fixtures." Wasted energy means wasted money. According to the IDA, $3 billion. Yearly. 

It's not just outdoor lighting that should be addressed, and Torkildson recommends pulling curtains to keep indoor lighting from shining outside. 

Just implementing these few steps can make a difference in helping to preserve our dark skies. 

Reducing light pollution helps us reconnect with the night sky and feel the sense of the awe our ancestors [were able to] take for granted. We are losing our common and universal heritage," Torkildson said.

Ways to get involved

*For more information check out, or the International Dark Sky Association at

*Watch the award-winning new film from PBS North (with Grand Portage resident T
ravis Novitsky), “Northern Nights, Starry Skies” to learn more.

*Check out the book "Spirits Dancing - The Night Sky, Indigenous Knowledge & Cultural Connections to the Cosmos" by Travis Novitsky and Annette S. Lee. Boreal Community Media talked with Novitsky about the book, which you can read here. 

*Learn about more Dark Sky-related activities happening this week from Visit Cook County.

 US Dept of Energy via IDA

Note: This article was originally posted on April 17, 2023, and updated on April 4, 2024.

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