Could Dark Skies Return To Chatham? The Answer Might Be Found On A Nearby Island

CHATHAM – Reclaiming the darkness of night by preventing light pollution is essential for human and environmental health, reasoned an astronomer at a talk held at the community center last Thursday. A nearby community, meanwhile, may be the case study in how to address the issue.

James Lowenthal, professor of astronomy at Smith College and president of the Massachusetts chapter of DarkSky International (a nonprofit for the movement to restore nighttime darkness), told dozens at the Earth Week forum, held by the Chatham Conservation Foundation, that there’s a handful of main points that would be gained by fixing light pollution: Better human health, more safety, better plant and animal health, less waste of energy and money.

“And of course, we'll get back the starry sky that our ancestors knew and loved and that all humans have turned to for inspiration,” Lowenthal said.

It’s a relatively new problem (thousands of generations have lived through very dark nights, only a couple have experienced nights flooded with artificial light) but the negative effects are profound. 

Among Lowenthal’s most startling pieces of evidence was a positive correlation between light-polluted areas and rates of breast cancers found in multiple studies in multiple areas. The scientific thinking goes that robust circadian rhythms are important for health, and repetitive and prolonged exposure to light disrupts those circadian rhythms. Furthermore, exposure to blue light at night suppresses melatonin production, which is a “powerful cancer suppressant," Lowenthal said.

“In the presence of melatonin in your blood, tumors do not grow fast,” he said. “In the absence of melatonin, tumors grow quickly. What your body is looking for, then, is a boost of melatonin — natural melatonin — as the sun goes down, to help your body fight tumors. It's an essential part of our immune system, and we are unfortunately disabling it. We're short-circuiting it with bright blue light at night when we're supposed to be producing melatonin.”

On the point of safety, glare from bright lights in fact reduces visibility. And Lowenthal said the link between light and crime is “actually much more tenuous” than one might think.

In terms of waste of energy and money, Lowenthal said the United States is estimated to spend at least $3 billion dollars a year shining light directly up into the sky.

“It's in Massachusetts on the scale of at least tens of millions of dollars. This is a very conservative estimate. It might be easily 10 times more, $30 to $50 billion a year spent on light that's totally wasted. Of course, producing that light requires producing electricity and producing that requires burning fossil fuels.”

Artificial light negatively impacts animals as well, including birds, fish and insects. Lowenthal said 100 million to a billion birds die because of light pollution in the United States (by distraction, disorientation or even confusion regarding migratory paths). Some species of fireflies have been threatened with extinction due to light pollution, according to Lowenthal, and the number of visits by pollinating insects drops considerably in areas illuminated at night.

Also, light pollution simply takes away the stars. According to one scale, Chatham’s night sky is 137 percent brighter than a naturally dark one.

“You really do have some nice dark skies there,” Lowenthal said. “It's so worth protecting.”

But how exactly is the dark sky supposed to be protected — or how can light pollution be prevented and restrained? There are certain steps that can be taken on an individual scale, especially for homeowners, like making sure light fixtures outdoors are pointed down (not out and up) and that the amount of blue light coming from those fixtures is minimized.

DarkSky International abides by five principles for responsible outdoor lighting, which are that lights should be useful, targeted, low-level, controlled and warm-colored. 

But then there’s the step steered on Nantucket by Gail Walker, who led the effort to get an outdoor lighting bylaw passed at town meeting in 2023 (Massachusetts, according to Lowenthal, is the only state in New England that has never passed any statewide control of outdoor lighting). Walker outlined the process to enact the legislation, which took three years. She first founded the nonprofit Nantucket Lights, then started to raise awareness about light pollution. 

Walker drafted the bylaw as a general one, not a zoning bylaw, so fewer votes were needed for it to pass, public schools weren’t exempt and preexisting nonconforming lighting could be required to be upgraded. The goals of Walker’s bylaw were to “minimize harm from light pollution, reduce energy consumption, and preserve the rural and historic character of the island, all while still ensuring there is adequate lighting for outdoor activities, safety, and security,” a Nantucket Lights document said.

The bylaw passed and went into effect at the start of 2024. Now Nantucket appears in brochures promoting tourism that refer to the island’s dark skies. With the bylaw for stricter outdoor lighting passed, Nantucket is also now in the compliance and enforcement phase, or challenge, of the process. Walker said they’re going for “cultural change” more so than regulatory enforcement. As in neighborhood pressure rather than fines may be the most direct path to darker skies on the Cape and Islands. 

“The night is about magic,” Lowenthal said. “It's not just fear and darkness and danger and crime. It's also beauty and wonder and stars and romance.”