Dimming the Lights

A boundless dome of darkness overhead – lit only by crystalline stars – is one of Maine’s most imperiled natural assets.

The Milky Way visible above Acadia National Park cannot be seen with the naked eye at any other national park on the Eastern seaboard, according to the National Park Service. In fact, this galaxy is no longer visible to nearly 80 percent of North Americans.

Eastern Knubble Preserve,Cutler. Photo by Eric Tirrell.

A sallow skyglow of light pollution is already overspreading portions of Maine. Unless we rethink our approach to lighting, we risk losing the celestial beauty that is the backdrop of our lives.

Growing light pollution represents far more than an aesthetic concern. It endangers wildlife, wastes electricity and disrupts circadian rhythms. Those collective impacts cost the United States nearly $7 billion each year, according to one recent economic estimate.

Constraining outdoor lighting at its source is feasible and affordable, but can be slowed by psychological and practical hurdles. A lighting transition requires – not just new bulbs and fixtures – but a commitment to illuminate only where and when it’s necessary, avoiding the floodlighting that tries to turn night into day.

Orange Mars and the Milky Way, as seen from Nutter Cove on Cobscook Bay in Lubec. Photo by Eric Tirrell.

The assumption that night lighting offers “security” needs to be reexamined. Daylight burglaries are far more common than nighttime ones, according to FBI data, and a British scientific analysis assessing 14 years of data from 62 communities found no evidence linking reduced street lighting to an increase in crime or in nighttime vehicle collisions.

According to the British Astronomical Association’s Commission for Dark Skies, more than half of Britain’s 468 local authorities now dim or turn off streetlights between midnight and 5 a.m. to save money and reduce greenhouse gas emissions. Maine communities could do the same, particularly those that are taking ownership of their streetlights following 2013 legislative changes enabling a transition from utility management to local control.

Rather than having lights continuously deployed to keep darkness at bay, we could activate them on an as-needed basis. Relying more on motion-sensors, timers and dimmers – for both municipal and household lighting – offers the added benefit of significant energy savings, particularly when relying on efficient LED (light-emitting diode) bulbs.

Municipalities and homeowners must select lighting upgrades carefully as the range and intensity of light pollution has actually increased since conversion to LED lights took hold. LED bulbs can generate glare and “light trespass,” and they can produce unhealthy blue tones that disrupt circadian rhythms.

Choosing lights with a correlated color temperature of 3,000 degrees or less on the Kelvin scale is essential for both astronomy and physiology (confirmed by the American Medical Association), explains Dwight Lanpher, a design electrical engineer and amateur astronomer on Mount Desert Island. Manufacturers predominantly made bulbs in the 4,000K range initially, he cautions, so retailers may try to lure in buyers with preferential pricing on those bulbs to reduce their overstock.

Echoing recommendations of the nonprofit International Dark-Sky Association (IDA), Lanpher counsels town officials and homeowners to select fully shielded light fixtures that direct light downward to minimize glare (what lighting engineers call full-cutoff, meaning that no light escapes above the fixture’s horizontal plane). With LED streetlights, he adds, it’s best to select fixtures that use lenses or reflectors to minimize glare.

Many Maine communities are now converting to LED streetlights, but far fewer (including Kennebunkport, Ellsworth and some of Mount Desert Island’s towns) have drafted or revised their ordinances or standards to reduce glare and light pollution from homes and businesses. That process can be time-consuming for town staff and volunteers, who may also lack means of  enforcement.

John Barentine, IDA’s director of conservation, acknowledges that enforcement is often “the weakest link in the chain,” and that lighting transitions are better predicated on “public support and voluntary compliance.”

Nearly a decade ago, in response to a 2009 Legislative Resolve to “encourage the preservation of dark skies,” the Maine State Planning Office issued a report recommending how communities statewide could transform exterior lighting. Rather than relying on local ordinances, it proposed an approach that would update automatically and could be checked by local code enforcement officers: adding outdoor lighting standards to the Maine Uniform Building and Energy Code.

That never happened. In fact, MUBEC still relies on the 2009 International Energy Conservation Code rather than the 2018 IECC as the Legislature has not yet approved an update. One bill this session proposes that update to MUBEC while another would permit towns to adopt “stretch codes” with more stringent energy efficiency standards. Neither proposal addresses outdoor lighting standards, so those changes would need to happen through rulemaking by the MUBEC Technical Codes and Standards Board.

Measures incorporated into MUBEC to strengthen energy conservation and protect night skies could bring unexpected economic and environmental rewards, especially if Maine retains skies sufficiently dark to become an astrotourism destination – drawing astronomy enthusiasts from around the nation and world.

Another state-level venue for preserving night skies, the Land Use Planning Commission, oversees roughly 46 percent of Maine’s land area (all its unorganized and deorganized areas). LUPC lighting standards adopted in 2004 were “pretty innovative” for the time, explains Samantha Horn, its planning manager. They require full cut-off fixtures, targeted lighting and elimination of nearly all after-hours nonessential lighting, while encouraging motion-sensitive lights.

But after 15 years, there’s room for improvement. Calls for more robust LUPC lighting standards in a recent rulemaking highlighted the “need to update our standards for new technology to better deal with brightness,” Horn says, as existing wattage limits were developed with incandescent bulbs in mind.

Limiting the light pollution seeping into Maine skies will take simultaneous action from state-level boards to individual bulb-changers. But every resident and visitor will reap the rewards. The more we reduce unnecessary outdoor lights, the more stars we invite back into our lives.

© Marina Schauffler, 2019. All Rights Reserved. Column reprints available upon request.


Promoting Quality Outdoor Lighting in your Community, a technical assistance bulletin produced by the Maine State Planning Office (2009) with diagrams and a model town ordinance for outdoor lighting

Report to the Business, Research and Economic Development Committee of the 124th Legislature in response to LD 11 (Resolve 2009, c. 22, To Encourage the Preservation of Dark Skies)

Dark Sky Planning: Guidance & Best Practices—An Introduction for Local Leaders, a manual produced by the International Dark Sky Association

“Our nights are getting brighter and Earth is paying the price,” in National Geographic, April 2019, https://www.nationalgeographic.com/science/2019/04/nights-are-getting-brighter-earth-paying-the-price-light-pollution-dark-skies/

Treasures of the Dark,” a Sea Change column I wrote in 2014, summarizes the rationale for protecting dark skies

Ecological Consequences of Artificial Night Lighting, edited by Catherine Rich and Travis Longacre (Island Press, 2006), provides  a longer scientific compendium on the damages of light pollution to wildlife