Wednesday, October 29, 2008

Light pollution

Something tells me I am going to take a lot of heat at the next dinner party for posting about this but I can't help it... I am concerned about light pollution.

This months print edition of Nat Geo discusses how nighttime artificial light distorts biological rhythms, disorienting humans and animals and disrupting natural patterns that have evolved without the hazy glow surrounding cities and the bright outdoor lights in our neighborhoods. Here is an excerpt from one of his posts, Ecological Light Pollution:

Humans have been aggressively lighting up the night for just over a hundred years, and though scientists have spent only a fraction of that time exploring the impact of the unintended peripheral glow on the natural world, observational and experimental data show that it affects how animals move about, communicate, find food, and even select mates. The most famous example is newly hatched sea turtles that become disoriented by the light from brightly illuminated beach communities and have difficulty finding the ocean. But behavioral changes have been documented in a wide range of species, including birds, mammals, insects, reptiles, and amphibians. Not all species respond to light in the same way. Many nocturnally migrating birds are drawn to the source and can wind up circling round and round lighted towers, often colliding with other birds or dropping from exhaustion. Some animals, such as mountain lions, avoid lighted areas at night; other species are able to exploit such areas—foraging longer or targeting prey that congregate near lights, as some bat species do. But the increase in foraging hours can have its downside, putting animals on the prowl at risk for predation. The overall effect on complex ecological relationships is not yet fully understood. There's also evidence that our grand transformation of the night might have serious implications for our own health. The contrast between dark and light allows our bodies to calibrate our circadian rhythms, such as hormone levels and sleep schedules. Disrupting these can have a dramatic impact. Researchers think this phenomenon may help explain higher breast cancer rates in societies with brighter nights. Studies on shift workers exposed to nearly constant light during the night hours reveal a higher risk for the disease, perhaps because of altered levels of melatonin. Other research shows that blind women have a lower occurrence of breast cancer. One study that looked at a general population also found a correlation between neighborhood nighttime light levels and breast cancer incidence.

Since reading Scriber's article, I can't stop hoping to see a truly starry night - but unfortunately live in between the sky glow from Washington DC, Baltimore, and Annapolis. He talks about what we used to (or should) be able to see as far as planets and constellations... it's upsetting. I am even thinking about going to the next (rather unbearable) homeowners association meeting to talk about replacing the enormous glowing street lamps in our 'hood with a model that reduces glare and focuses light downward.

The entire article is currently only available in print and online to subscribers, but I recommend picking it up or at least reading the article abstract and some posts by the author here.

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