September 2026: Lighting for Reassurance, Light Pollution News

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This Episode:

You’ll want to tune in for this one! This episode, I’m joined by plant phenology ecoligist, Dr. Lin Meng and Dark Sky Consulting, LLC’s John Barentine!

Dr. Meng discusses a new exploratory study her team did covering four major East Coast urban areas! How do we bridge divides between residents, municipalities, and science. And did you know that an artist from right here in the United States created his very own version of Stonehenge! Find out where next, on this episode of Light Pollution News!

Host:

Guests:

John Barentine

John Barentine is an astronomer, historian, author, science communicator, and dark-sky consultant. He earned a Ph.D. in astronomy from the University of Texas and is a member of the American Astronomical Society, the International Astronomical Union, and the Royal Astronomical Society. His interests include history, politics, and law.

Lin Meng

Dr. Lin Meng is an Assistant Professor in the Department of Earth and Environmental Sciences at Vanderbilt University. As a global change ecologist, she studies how human activities affect urban ecosystems and how cities can become healthier and more sustainable. Her research has shown that urban heat and light pollution can alter the seasonal rhythms of trees, leading to earlier spring growth, later leaf fall, longer pollen seasons, and higher pollen allergy risk. Her work helps connect changes in the urban environment with their consequences for both ecosystem health and human well-being.

Full Article List:

1. How to Grieve a Changing Planet, Phil Lane MSW, LCSW, Psychology Today.
2. Mitigating artificial light at night: effectiveness of policies and implications for plant phenology, PNAS Nexus.
3. The illusion of control: Do we need dark infrastructures to address light pollution?, Environment and Planning E: Nature and Space.
4. Guy Ottewell honored with an asteroid in his name, EarthSky.

Light Pollution News: September Highlights

“Eco-Grief” and “Noctalgia” Capture the Emotional Toll of a Changing Planet and Vanishing Night Skies

Eco-grief is a broad term for the sense of loss people feel as human activity drives irreversible change to the natural environment. A related, narrower term, “noctalgia,” was coined by astronomer and dark sky researcher John Barentine specifically to describe grief over the loss of naturally dark night skies to light pollution.

PNAS Nexus Study Finds City Lighting Laws in New York and Washington, DC Reduced Light Pollution and Shifted Plant Growing Seasons

A PNAS Nexus exploratory study compared artificial light at night and plant phenology in New York City and Washington, DC, both with lighting-reduction laws, against Newark and Philadelphia, which have none. Between 2022 and 2023, artificial light fell 4-5% in New York and 8-10% in DC, with a notable drop in blue-spectrum lighting in DC. The policy cities also saw spring leaf-out delayed about 4 days and autumn leaf color arrive 7-9 days earlier than in nearby non-policy cities.

2021 Ecology and Society Study Proposes Protecting Darkness Through Connected “Dark Ecological Networks”

A 2021 Ecology and Society study proposed protecting darkness through connected “dark ecological networks,” treating it the way conservationists treat forests or rivers rather than isolated dark sky parks. The researchers found artificial light fragments wildlife habitat like a highway, but that turning lights off — not just dimming them — removes that barrier effect, and called for extending dark sky protection to ordinary towns through collaboration between scientists, residents, and officials.

Follow-Up Study in Environment and Planning E Finds France’s Trame Noire Dark Sky Policy Fell Short in Practice

A 2026 follow-up study in Environment and Planning E, from largely the same team behind the 2021 dark ecological networks paper, found that France’s Trame Noire policy operated in practice through zoning maps and optimization software rather than local collaboration. The approach neither changed lighting behavior nor reduced light pollution, largely just legitimizing existing lighting as-is. The study recommends municipalities move beyond zoning maps and formally inventory “lit infrastructure” to reframe policy around reducing overlighting.

South Downs National Park Reintroduces Glow Worms to Reverse UK Population Decline

South Downs National Park in the UK is reintroducing the common glow worm to a new site, aiming to boost the declining beetle’s numbers in a project comparable to firefly conservation efforts in North America. The park has held International Dark Sky Reserve status since 2016, and the newly introduced larvae, sourced from Devon, are expected to reach adulthood by summer 2027.

Sleep Study Links Bedroom Light at Night to Higher Rates of Obesity and Hypertension in People With Schizophrenia

A study in the journal Sleep found that people with schizophrenia exposed to the brightest nighttime bedroom light had 4 times higher odds of obesity, 3.4 times higher odds of hypertension, and 2.4 times higher odds of dyslipidemia than those with the least exposure, along with roughly 22 more pounds of body weight and a 3-inch larger waist circumference on average. The cross-sectional study tracked 222 schizophrenia outpatients using wrist-worn light sensors and bedside light meters over seven nights. Two study authors disclosed prior, unrelated grants from circadian-lighting and “healthy home” companies, though those grants did not fund this research.

Astronomer Guy Ottewell’s Path Into Astronomy Began While Teaching on a Navajo Reservation

Astronomer, artist, and Astronomical Calendar creator Guy Ottewell spent much of his early life pursuing interests outside astronomy entirely, only looking through a telescope for the first time while teaching and collecting Navajo star lore at a school on a Navajo reservation. He has since become known as a wide-ranging polymath, with additional work in archaeology, anthropology, botany, computer programming, painting, and poetry.

Light Pollution News: September Read Along

I want to start off today’s show with this idea of ‘Eco-grief’. John, I believe you coined a variant of this called ‘Noctalgia.’ The latter being specifically related to the loss of our night sky. ‘Eco-grief’ would be an all encompassing concept that, here in 2026, we’re sitting on the precipice of a world where humans are about to irreversibly terminate the natural environment from the way that we’ve largely come to know it.

Lin, you recently were part of an exploratory study out of PNAS Nexus which looked at four cities: New York City, Washington, DC, Newark, NJ, and Philadelphia. You wanted to know if city laws designed to reduce unnecessary artificial light at night actually did what they set out to do. Further, you asked if these reductions in unnecessary light affected plant phenology.

Now, the data was all satellite driven, and the paper found that, by and large, the laws appear to have worked at a macro level. NYC saw a reduction by 4-5%, and DC saw a reduction of 8-10% between 2022 – 2023. It was noted that blue light band lighting noticeably dropped in DC as well.

In springtime, the cities with policies started leafing out later by the tune of 4 days. In autumn, things reversed, and leaves in those same cities began changing color about 7 to 9 days earlier than in their non-policy neighbors on the 95 corridor. This showed a consistent trend toward shorter, less light-disrupted growing seasons for cities that had laws on the books.

As an aid to this conversation, there’s this idea of dark infrastructure deriving from an idea of darkness corridors. This was notably spoken about via a 2021 study in Ecology and Society. The paper introduced an idea of dark ecological networks, essentially arguing that we should treat darkness the same way conservationists treat forests or rivers by protecting them via connected corridors. It was understood that artificial light fragments habitat the same way a highway does, with one caveat, that simply turning lights off eliminates the ‘highway effect.’

Rather than just protecting touristy dark sky parks, the researchers wanted to network darkness around your average town. The team mentioned that this would best be implemented through conversations between scientists, residents, and local officials.

Fast forward to this year, a team with many of the same authors revisited their earlier paper with a more skeptical follow-up, published in Environment and Planning E: Nature and Space. This assessment looked at how a similar approach played out in France’s Trame Noire policy. Contrary to the initial hopes of the 2021 study, the team found that in practice dark infrastructure operated out of zoning maps and optimization software, not local input and collaboration. And unsurprisingly, this practice didn’t lead to positive behavior shifts, nor a reduction in light pollution, rather, it simply legitimated current lighting as is.

The new study claims that a policy of dark infrastructure defines darkness as an inflexible idea. Rather, it kept the community and science input on opposite ends of the decision making. Instead, to correct that, communities should opt away from the zoning maps and embrace dark areas in the planning process. Second, communities should inventory and give a name to ‘lit infrastructure’ in hopes of flipping the script from darkness to overlighting.

I want to give you folks with me today the opportunity to plug yourselves. But before we get to that, I found this fun piece regarding our glowing insect friends. Over in the UK, officials in South Downs National Park will be introducing a European glow worm with hopes to help boost the beetle’s numbers in the UK. Similar to fireflies here in North America, glow worms are a dwindling insect.

South Downs gained Dark Sky Reserve status back in 2016. The larvae are expected to become adults by 2027, and no doubt will add to the awe and wonder of the nighttime park.

I have one piece of health news that aligns with this conversation point. This is from Sleep, and it asked the question of whether light at night in the bedroom or sleep environment is associated with metabolic health issues for schizophrenic individuals. It should be noted that folks with schizophrenia tend to suffer from higher rates of metabolic problems than the general population. The study looked at 222 patients, with a median age of 50, who were outpatients recruited from hospital settings. None of the participants worked night shifts nor had any serious psychiatric symptoms as assessed by a clinician.

Participants wore devices on their wrists that measured light exposure and movement for seven nights, and also had beside photometers placed near their heads at eye level to identify nighttime light exposure from when the individuals reported they went to sleep to when they woke up. They drew blood samples and performed physical exams of each individual. They put individuals into one of the four groups and defined those groups by the average nighttime light exposures, be it from the dimmest to the brightest groups.

The findings here showed that for the group with the brightest nighttime setting, they had 4x higher odds of being obese, 3.4x higher odds of hypertension, and 2.4x higher odds of dyslipidemia (which, for you at home, if you’re anything like me and have never heard of that word before, simply means having a greater amount of unhealthy cholesterol and triglycerides). In fact, the brightest group had 22lbs more body weight and roughly a 3” larger waistline.

Contrary to other studies, they didn’t identify a diabetes risk, for which the team claims that very few folks in the study had diabetes to begin with, but, and this was really interesting, the HbA1c, a test that measures blood sugar, was linked to be higher for folks in the brighter group.

Between the two devices used to measure nighttime light, the wrist device appeared to be more accurate because it captured light exposure if someone, say, had to use the bathroom at night. Which brings up an interesting point, just maybe the light outside of the bedroom matters equally as much as the light entering the bedroom? And by outside, we can interpret that as meaning, say, a bathroom or hallway light. It’s an interesting idea, though one not tested for here.

Before we move on, I do want to let you know some caveats with this study. Two main things, first, this study by design cannot prove causal relationships. This is only a cross-sectional study, in order to pull out a causal relationship, it would need to be a longer duration study, ie longitudinal design. Also, while this study’s funding derived from the Takeda Science Foundation, the Japanese government, the study had two authors who previously received research grants from some lighting and home building companies. I looked into them briefly and, as I expected, these companies have products that focus on circadian lighting
and “healthy home” building. Those grants were not used to fund this study.

Let’s close out this month with some map making. Specifically, I have two articles on two men who have had an outsized influence on how we see our night sky.

First, I bet some of you are familiar with the name Guy Ottewell, though I’ll embarrassingly admit that I was not. Ottewell is best known for his sky charts, which were published in Ottewell’s Astronomical Calendar for 43 consecutive years between 1974 and 2016, though I will note that the calendar has been published periodically since then. Ottewell wrote the Astronomical Companion, which, among other things I found interesting, had very practical 3-D mappings of how we see our solar system, constellations and the general universe. Think of it as a print version of Sky Safari. Ottewell turned 90 on the 4^th of July, and was promptly given an asteroid of his name via the International Astronomical Union two days later.

In the same vein as Ottewell, though a bit more narrowly focused, we have the artist Charles Ross. Now, truth be told, I was alerted to him by the New York Times, but I didn’t actually read the article. Rather, I looked up his art. But first, just a little about Ross. He originally grew up here, in the Philly suburb of Glenside. Nearby, Yankee great Reggie Jackson would later grow up.

Ross’ art almost wholly focuses on the connection of light, time, and the sky. Over on his website, he has some stunning art that resembles star maps and the motions of the planets. However, what I presume caught the NY Times’ eye was his decades long work called Star Axis. It’s a facility in New Mexico that is a throwback to, say, Stonehenge, where everything is designed based on astronomical calculations and positions. This is one that you have to just see for yourself. You’ll see the link on the show page for this episode. It’s quite an amazing feat in any age, but more so, I’d argue, in today’s age where we have all but detached ourselves from the second half of the day.

You know what I found interesting about Ottewell was that for much of the first part of his life he had done everything but astronomy. It wasn’t until he taught the Navajo and started to learn Navajo stories did he even look through a telescope for the first time! He showed himself to be quite the polymath, with interests in archaeology, anthropology, botany, coding, painting, poetry, and the list goes on.