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Editorial Archives — The Altamont Enterprise, September 1, 2011

Curbing light pollution will help restore natural balance and protect human health

Consider the sea turtle.

As tiny hatchlings emerge from their nest on the beach, they find their way to the sea by moving away from the dark dunes. They have followed this pattern — distinguishing darkness from light — for centuries.

But what if the dunes are no longer dark? What if the lights of human civilization cast their glow where the black of night once reigned? The hatchlings become disoriented and cannot find their way to the ocean. They die.

We human beings have, for over a century, lit up the night. Nearly two-thirds of the world’s population live under sky brightness higher than baseline levels, according to studies published in the Journal of Pineal Research; in the United States and Europe, 99 percent are exposed to brighter than normal skies.

The ecological implications are deep and far-reaching. The sky glow in urban areas is brighter than a natural twilight and in some cases brighter than a full moon. This affects migration patterns, reproductive cycles, and foraging. In short, it upsets the natural order.

One familiar example of the effects of light, used for decades, is that hens can be stimulated to lay more eggs in the winter by putting lights in their coop. Since these are domestic birds, their survival is not at stake. But what if the bird is in the wild?

A study conducted in Edmunton, Alberta by W. Ronan where juncos were exposed to electric lights at sunset for several minutes each day in the midst of winter caused the wild birds to come into a reproductive condition despite the harsh Canadian cold. The same was true with European field voles.

But we humans are not just wreaking havoc with the natural world, we are affected as well.

In the last half-century, electric lighting has changed from incandescent bulbs — with mostly low-level yellow wavelengths — to a high-intensity discharge form with blue wavelengths. The ganglion cells in our eyes that detect light and suppress melatonin production are most sensitive to blue/violet light. Studies published in the Journal of Pineal Research have shown that exposure to incandescent lighting for less than an hour can result in a 50-percent decrease in circulating melatonin levels, and exposure to even very low levels of blue spectrum light — no brighter than moonlight — results in melatonin suppression.

Known as the “hormone of darkness,” melatonin is produced by the pineal gland in the brain; its release is triggered by darkness. Melatonin secretion peaks in the middle of the night and then gradually decreases towards dawn. The Circadian pacemaker organizes the timing of the whole human body and its multiple systems, all triggered by light.

A host of problems are associated with disruption of this natural Circadian rhythm, ranging from obesity to cancer. About 15 percent of American workers work a shift other than a daytime schedule. Constant lighting conditions alter the rhythm of a number of hormones.

Exposure to a low-level incandescent bulb at night takes only 39 minutes to suppress melatonin levels to 50 percent, according to the Journal of Pineal Research; such changes in melatonin production and release regulate metabolism, immune functions, and endocrine balances. Recent studies have focused on the link between exposure to artificial light at night and the prevalence of breast and colorectal cancer.

So, what’s to be done?

Clearly, we can’t turn back the clock to a pre-industrialized society. If our cities are to stay safe and our traffic is to continue to flow, we need artificial lights.  Because most of us in modern America have grown up with extensive artificial light, we tend not to see it as a problem.

Understanding that it is a problem will help us to solve it. Cities around the world have been leading the way in reducing light pollution. Calgary, for example, has replaced most residential streetlights with a less polluting model; the lights’ efficiency is expected to pay for them in six or seven years with savings in electricity.

The Lombardy region of Italy now requires a full cutoff design to prevent light pollution; as a result, it has the lowest per capita public-lighting energy consumption in the country.

Here, in the United States, Flagstaff, Ariz. has worked on ordinances and public education for over three decades to successfully reduce light pollution, making the United States Naval Observatory there functional.

And, in our own Helderberg Hilltowns, the town of Knox has joined the international movement for dark skies. Last month, in a split vote, the board passed zoning that requires all new construction to use only full-cutoff light fixtures.


The Knox Planning Board was inspired to draft the zoning amendment because the Dudley Observatory was interested in using Knox with its rural dark skies for star parties.  We certainly appreciate the advantages of dark skies for professional astronomers and amateur stargazers alike.

But, as we’ve outlined from the start, the advantages to curbing light pollution go well beyond that, benefiting the health of ecosystems and humans alike. Indeed, two years ago, the American Medical Association endorsed a policy supporting control of light pollution. We urge other municipalities to follow Knox’s lead.

Full-cutoff fixtures were first produced over a half-century ago by General Electric in Schenectady. They keep light from escaping upwards, focusing it, instead, on the ground. This not only reduces sky glow but saves energy and money. Municipalities can also space their lights further apart to save on pollution and money.

The Knox ordinance, though, goes beyond municipal lights. It requires all new fixtures to be full-cutoff lights. This won’t be burdensome for residents, since lights don’t have to be retrofitted. Although, in Knox and elsewhere, homeowners and business owners may want to replace their less efficient outdoor lights with ones that are better for both the environment and their pocketbooks.

Making such changes will ensure a brighter future for all of us.

Melissa Hale-Spencer

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