James Lowenthal first began observing the night sky 50 years ago through a telescope he made all by himself, catching a glimpse of Saturn’s rings. But it wasn’t just the lights in the sky that became important to Lowenthal, who is now a professor of astronomy at Smith College.
“What I’ve come to appreciate over the years is how much more there is to darkness at night and how we actually totally depend on it,” Lowenthal said. “And as a culture, we’ve lost sight of that. But we’re regaining it.”
Lowenthal is a member of the steering of Northampton City Lights, a group dedicated to reducing light pollution in the city. And as International Dark Sky Week begins on April 21, Northampton organizers plan to honor the occasion with their third annual Night Sky Fest. The event will feature stargazing, observing night sounds and animals, announcement of an application for certification to designate Northampton as an Urban Night Sky Place, and a proclamation from city officials formally recognizing April 21 through 28 as International Dark Sky Week.
The event is scheduled for Tuesday, April 22 at 8 p.m. with a rain date of April 26.
The Northampton City Lights organizers, who aim to fight light pollution and “improve safety and quality of life for all,” are tied into broader organizing efforts by the non-profit DarkSky International. The non-profit was founded 37 years ago by professional astronomer David Crawford and physician and amateur astronomer Tim Hunter to “preserve and protect the night time environment.”
These organizations aim not only to preserve visibility of the stars and celestial bodies, but to combat the harmful impacts of artificial light pollution. These impacts range from potentially increased risk of several types of cancer and neurodegenerative diseases to alteration of night air chemistry contributing to decreased air quality. Light pollution also has wide reaching impacts on wildlife and their relationship to the environment.
Lowenthal discussed the importance of natural darkness and the “dark sky movement” in an interview with The Shoestring.
“The dark sky movement is an international movement of people of all different stripes, some astronomers, but really mostly people from all different walks of life,” he said. “Including lots of non-academics and just regular people who recognize darkness at night is something we need. And we need it for cultural reasons, biological reasons, ecological reasons, scientific reasons, and those are gaining traction, even at the same time as we add more and more artificial light at night.”
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DarkSky International’s “State of the Science 2024” report — which summarizes the current scientific understanding of light pollution from 448 international research studies and publications — shows how artificial lights affects the environment and outlines strong links found between artificial light at night and negative impacts on human health, wildlife, and ecology.
A lot of the negative impacts of night lighting are driven by the color of the light and the shape or design of lighting fixtures.
Many energy efficient lights available in the public market today are composed of multi-colored LEDs, or light emitting diodes, many of which contain a spectrum of blue light.
In the natural environment, blue light is most prevalent in the daytime, while red light is more prevalent at sunrise and sunset. These natural shifts of light color signal to plants, animals, insects, and humans the changes between day and night. Disruption to these light signals is a driving force behind many of the negative impacts being linked to artificial light at night.
“Light pollution is a death by a thousand cuts kind of problem,” Lowenthal said. “If you have a really dark environment, one light will ruin it, and so everybody’s light adds up.”
“When the sun goes down, the amount of blue light in our environment drops dramatically. The blue sky and everything else, and your eye detects that,” Lowenthal said.
Our eyes not only contain cones and rods which give us vision but also contain cells that function as a sort of “detector” within the retina of our eye that sends signals to the brain to start producing melatonin when the blue light in our environment drops, according to Lowenthal.
“Melatonin is the hormone that plays a role in resetting your 24-hour clock, your Circadian rhythm, your biological rhythm, which everybody has, but most people don’t think about very much,” he said. “It affects all these other hormones and resets your digestion, your respiration, your temperature, your sleep, fullness, and wakefulness. Melatonin is also a powerful cancer suppressant. It’s a tumor suppressant.”
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Studies on mice and rats have found a significant link between exposure to blue artificial light at night and impacts on melatonin secretion affecting the entire lifecycle and health of the animals. While it is challenging to replicate controlled light exposure studies in humans, anecdotal evidence from a meta-analysis of research on night-shift workers further substantiates this link and establishes that artificial light exposure at night leads to epigenetic changes in humans — changes that alter the roles of our genes. This alteration to the function of the genes that regulate our circadian clocks can increase the risk of cancer.
Research has also found connections between light pollution and mental health decline. A 2018 study found evidence of associations between exposure to outdoor lighting at night and increased rates of suicide and depression.
The effects of light pollution on human health are also interlinked with the impacts of light pollution on plants, animals, and the relationships they have with each other in the environment.
A large amount of all plant pollination is driven by nighttime pollinators, and artificial light pollution can disrupt pollinators from reaching plants. Natural light cues also signal to different species when to come out of their hiding places and look for food or mates for reproduction. Disruption of lighting cues has also been observed to impact seasonal cycles of plants, inhibit species migrations, and can contribute to impacts on food production, like decreased yields and delayed food production.
Lowenthal told The Shoestring that thoughtful lighting that protects the skies doesn’t necessarily have to come at the cost of safety.
“Safety and visibility, that’s what lighting promises, and it’s a big promise,” he said. “The promise is it’s all going to be better. It’s gonna be safer. The more light you have, the safer it’ll get. That’s a very common assumption. As a result, we over-light everything. We have way more light than we need, and in fact, we have way more light than is good for us.”
He compared excessive lighting to excessive water intake. While drinking water is important to your health, drinking water in huge excess is actually harmful to your health and even lethal.
“There’s a pretty low threshold above which more light doesn’t actually help safety, or security, or visibility,” Lowenthal said.
Research on lighting impacts related to road safety, pedestrian safety, and crime are mixed, with researchers repeatedly finding challenges in establishing controlled study conditions. There is no universal scientific evidence basis, to date, that establishes recommended lighting levels for safety.
So how do we start addressing harmful lighting?
Lowenthal said to start on your own front porch, or by talking to your neighbors. He said starting those tough conversations is a great place to start, and even offering to cover the cost of a different light bulb for your neighbor can lead to positive change. Beyond that, policy and legislation are the next options.
Massachusetts is the only state in New England with no statewide regulation on light pollution, according to Lowenthal. He said cities and towns, however, do have strong regulatory abilities under the state’s home rule petition process, and well crafted ordinances can regulate not only municipal lighting but also private lighting.
These ordinances could be used to place restrictions on the types, and color, of lighting being installed to replace damaged or outdated energy intensive lighting. For example, restricting new lighting installations by their kelvin settings, or color temperature, would be a step toward mitigating some forms of light pollution. Lights operating at higher kelvin numbers, especially above 3,000 K, simulate lighting that is similar to bright daylight, while lower Kelvin numbers are more similar to lighting that occurs around sunrise and sunset.
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One Massachusetts town that has recently made huge strides in reducing not only its light pollution, but also its energy consumption, is Shelburne. The Shoestring took a nighttime field trip out to the Franklin County town to see the difference thoughtful lighting can make.
Jeff Boettner, a retired wildlife biologist, has been the chair of the Shelburne Streetlight Committee, whose final day of existence was Friday. Boettner is also the chair of the town’s energy committee.
Through the hard work of these committees over a two year period, Shelburne was able to do something amazing to witness in person: they replaced their town’s lights with energy-efficient lighting that also preserves the natural darkness of the night sky.
Earlier this week, from a street on a hill overlooking the town, only a few twinkles of golden light could be seen below. Despite having around 100 streetlights, looking down on the town looked a bit like looking at a starry night sky: some points of small light, but mostly nighttime darkness. On the streets and sidewalks themselves, however, the streetlights provided plenty of light to navigate. Standing right beside one of the street lights, you can gaze right up into the sky without much interference, or glare, from the light.
Boettner showed The Shoestring how this was possible with an unmounted streetlight he had at his home. The lights, which the town purchased from Cooper Lighting Solutions, have multiple features designed to control the direction of the light emitted from the LEDs. Some of these features are shields that can be placed on or over different parts of the light, depending on what type of area you are trying to light and what light pattern would best serve the area you want to light.
These lights also allow for adjustments on individual lights, and time-specific dimming, through a top-mounted attachment called a “Dimmulator.” Boettner said the town has selected to dim its lights by 30% between 10 p.m. and 5 a.m.
“Originally, it started when Eversource wanted to give the town ‘free’ LEDs,” Boettner explained. “That would have saved the town around $5,000 a year, but we would still depend on Eversource for electricity and maintenance of about $10,000 a year.”
Boettner said the offer was tempting, and the town agreed to a test demonstration of the lights. The test lights were widely disliked, he said, and despite multiple adjustments from Eversource — including an attempt to create their own shielding devices to stop the lights from shining into people’s homes and bedrooms — the community was not looking forward to the result of the new lights.
A petition signed by over 300 people was brought forward to oppose the Eversource lighting, and thus the Shelburne Streetlight Committee was formed.
“We talked to a number of towns and learned that most were choosing to do their own lighting and saving more by having control over the maintenance, “Boettner said. “We visited towns in Massachusetts, New Hampshire, and Maine to see what others were using.”
The committee ultimately found they liked the lights used by the Massachusetts town of Pepperell the most, and modeled their approach off of that.
The town hired consultants to help them pick the best lights for their needs, and those consultants compiled an interactive database that they can use to look at the specifics of each streetlight in town. This will be useful down the line as the town takes on future maintenance of the lights.
By comparison, other municipalities like Northampton and Easthampton have updated some of their lighting in recent years for energy efficiency, but compared to the lights in Shelburne, they still have a lot of progress to make.
The recent installation of an illuminated billboard sign in front of Easthampton’s Public Safety Complex, for example, seemingly did not take light pollution or hazards from glare into consideration prior to installation.
While Northampton has made a proclamation acknowledging Dark Sky Week and the significant problem of light pollution, and aimed to establish standards for outdoor lighting, they have declined repeated requests to convene a streetlight committee, according to Lowenthal.
Northampton Mayor Gina-Louise Sciarra did not immediately respond to a request for comment on Thursday.
So how much did this lighting conversion ultimately cost Shelburne?
Boettner said the town approved $75,000 for the project by unanimous vote — an unusual agreement of total consensus, he said. And while the town is still running official numbers, the cost is well below that amount.
“We were able to use $11,000 in federal ARPA money for initial studies, $48,000 from a state Green Communities Grant, and $12,000 in Mass Save incentives for reducing energy consumption,” Boettner said. “Plus, we were able to save by taking down some redundant lighting, and by getting the lights up in half the budgeted time and other cost cutting moves.”
Boettner said that in the end, the cost to Shelburne will be only around $2,000 or roughly $1 per resident. And the annual savings on maintenance should cover even these costs in about four months.
A few challenges still remain. Some of the Eversource poles on which the lights are mounted need replacement, for instance.
“It’s not perfect,” Boettner said, pointing out some of the old poles leaning at angles that made directional lighting a challenge. “We still have some places where light is reaching the houses a little more than we would like.”
“We are still adjusting the lights a bit, but overall we feel it was a huge success,” he added.
For those looking to mitigate their own light pollution impacts, or perhaps engage with their municipal bodies about light pollution, Boettner said to reach out to him directly at boettner@umass.edu .
The Northampton City Lights organization and the DarkSky International website also host a wide variety of information and resources for people, and municipalities, looking to learn more about lighting. Those resources range from research studies, to lighting education for renters and homeowners, to locations of “dark sky places.”
“The other thing to keep in mind is we’re not saying, ‘Get rid of all lights and make every city black.’ Nobody’s saying that. We are not the Dark Ground Association. We are DarkSky International — dark sky,” Lowenthal said. “We just don’t want the light shining up into the sky, and we want to use light responsibly.”
“I need the dark night and I’ve always loved it and I’ve always kind of been a night owl. But apart from that, I’ve always just loved being out under the stars.”
Update: This article has been updated to correct the spelling of the name of the non-profit DarkSky International.
Tommy Lee is a writer, investigative journalist, and audio video producer for community television based in Western Massachusetts.
