After taking observational astronomy in the Spring, I have found myself looking up at the night sky more and more, learning stars, planet, and constellations (via the incredible app Night Sky 2 https://itunes.apple.com/us/app/night-sky-2/id649020636?mt=8). I was surprised that little Athens, with its environmental reputation and surrounded by green hills, cast such a bright footprint that much of the night sky is drowned out. With so many other environmental issues, why does light pollution matter? especially here in old coal country and newborn fracking country, what is the big deal with not being able to see the Milky Way? My research showed a lot of surprising impacts including wildlife, human health, and general energy waste. I also was happily surprised with how simply light pollution can be solved, and with the actions Athens has taken towards it.
As diurnal animals with eyes adapted for daylight, we prefer light over darkness. Because of this we consider lighting the night positively, increasing safety and reducing crime, without reflection on consequences. Light pollution is light that spreads where it is unneeded and unwanted. Light that crosses from your neighbors yard into your bedroom, light that blinds you with glare, and light directed up that floats away pointlessly and uselessly.
Light pollution is a blatant form of waste, and yet are apathetic to all exterior lighting. 8% of all domestic energy use goes to public lighting, and much of this is waste. Excessive light, glare, and light directed towards the sky rather than towards the ground results in an economic loss of 2.2 billion dollars. Interestingly, the benefits of night time lighting are also extremely overstated. It is assumed that lights reduce crime, but studies on lights and crime have been a mixed bag, some showing reductions while others show no impact or increases in crime.
The impacts of this waste extend beyond the economy and the obvious emission contributions from energy production. Nighttime lighting has only been used since the late 19th century, and has only recently grown to the massive levels we see today. Humans and all other life on Earth has evolved with approximately even amounts of light and dark. It follows that disrupting these cycles has impacts. Many people have heard that since the invention of electric light the average amount of sleep has decreased from 9 hours per night to 7.5. This is due to lights effect on the brain. Light makes the brain stop production of melatonin, the anti-carcinogenic hormone which induces sleep. The disruption to circadian rhythms caused by light at night have been linked to breast cancer, obesity, diabetes, depression, mood
disorders, and reproductive problems. Nighttime lighting has been so detrimental to human health that the American Medical Association has advised policies reducing night lighting.
Most studies on light pollutions impacts on animal life have focused on migratory birds and sea turtle hatchlings. Many birds navigate by the stars when they migrate. The light of cities attract these birds, and once the birds enter the cities they can no longer see the stars. Many of the disoriented birds, some estimates are as high as 2 billion birds per year, perish by flying into glass, or by exhaustion as they seek a way out of the city. Sea turtles lay eggs timed to hatch with the full moon on beaches oriented with the moon rising over the ocean. The glow of the moon guides the hatchlings away from predators to the safety of the ocean. Light pollution from hotels and roads near beaches draw the turtles in the wrong direction resulting in loss to predators, traffic, or dehydration.
Solving this problem is simple, only use light where it is actually needed. Dimmers, motion sensors, and most importantly lights that are shielded to direct lightly only below the horizontal plane. Athens has been fairly proactive in this having light pollution standards on all new construction for about 10 years. The Richland Bridge is a good example of responsible, well-planned lighting. However the ordinance only applies to new lights and Ohio University is exempt, so much more can be done.
More information can be found at:
The International Dark-Sky Association - http://www.darksky.org/
The City Dark - PBS documentary available on Netflix
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