|Moonrise over the city, as seen from Ashland and Lake CTA Station|
Donnie R. Dann
Volume 16 Number 4 July 2012
During the long history of life on earth, both for animals and plants and then for humans when they came on the scene, the source of visibility at night was primarily celestial objects. Next in our evolutionary history came controlled firelight which provided limited night illumination until the relatively recent development of electric lighting.
Today we've become so acclimated to artificial light we don't even think about its impact, both on people and wildlife. Granted, night lighting is essential to our industrial society and the lifestyle to which even remote outposts of civilization have become accustomed. But consider its downsides and the well-documented adverse impacts extensive night lighting hasworldwide:
• Research shows our natural body clock and circadian rhythms (and potentially our health) are affected by lights at night .
• Night lighting increases air pollution .
• Birds, bats and other migratory wildlife use several clues in their (mostly) twice yearly journeys but starlight is an important one, and extensive night glow can be highly disruptive to the celestial clues these migrants track.
• Plant life is also seriously affected. One example are the many species of cacti that bloom only at night and their pollinators that are night flying insects and bats. One especially beautiful cactus, the Queen of the Night, opens at night for only a few hours or so and they simply can't reproduce with excessive light. And if the flowers are gone so too are their plant specific pollinators.
• Does this even matter to humans? Scientists estimate that 1/3 of all human food is dependent on pollinators and disrupting the food chain on a planet that evolved for millions of years with fixed daylight and nighttime time periods could ultimately wreak havoc on our food supply and on us. See the National Academies Press' booklet “Resourceson Pollinators”
• Lighting that reflects upward not only lightens the night sky but is wasted energy. The International Dark Sky Association estimates we waste 22,000 gigawatt hours a year, which at 10 cents per kilowatt hour amounts to $2.2 billion annually.
• Populated areas have lost the ability to see and experience the wonder of our starry sky. Safety is paramount in considering the benefits of night lighting. Can we be safe by lighting our way at night without bringing harm to ourselves and our ecosystems? Here are just 2 examples:
• Outdoor lights for roads, businesses and outside your home can have a shield on top, directing all beams downward.
• Several cities, including Chicago have adopted “Lights Out” programs whereby many tall buildings voluntarily turn off their office lights during migration, thereby minimizing collision danger as well as lessening the confusion factor to which birds and bats are prone. This is to say nothing of the energy savings and potential pollution that's avoided (see bullet 2 above).
For an excellent resource on this entire problem I urge you to consult a book edited by Catherine Rich and Travis Longcore, “Ecological Consequences of Artificial Night Lighting” (Island Press). These issues have been extensively reported and the editors summarize the seriousness of the problem and most importantly the solutions, many of which we can all adopt.
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