Wired News reports that scientists and astronomers have formed the Dark Skies Awareness group, which as part of the 2009 International Year of Astronomy is going to lobby for people to turn out the lights. The group reports that a fifth of the world's population cannot see the Milky Way because of light pollution.
Light pollution is a serious problem for astronomers. At the Palomar observatory in California, city lights are now directly observable through a gap in the mountains. According to Dave Kornriech with Cornell University, "Many observers have given up looking at objects in the southwestern sky, because the light pollution is so bad in that direction." He adds that if the current trend of growth with the neighboring city of San Diego continues, "in the next ten years or so, Palomar will be useless for deep-sky astronomy." The Mount Wilson observatory outside Pasadena has already been decommissioned due to the encroachment of urban light pollution. Although many other observatories in remote locations are unaffected at this point, one wonders, how long will it be before they too are rendered useless?
Whenever I talk about this to someone, inevitably the first thing they say is, "Turn out the streetlights? That's stupid! People will die in traffic accidents!" (Or something along those lines.) Fortunately, no one is asking cities to turn their streetlights off. However, properly shading streetlights so that the light points down instead of up would both improve streetlight efficiency, and reduce the amount of ambient glow in the sky. Most street lights pour as much light uselessly into the sky as they point down onto the street.
Buildings - both residential and office - are also culprits. Leaving the lights on at night inside an office is not just a waste of money, it is contributing to light pollution. At home, many people install bright lights which shine all night, from dusk until dawn. Does the front of your house really need to be lit up with daylight intensity, 24 hours per day? Homeowners concerned about safety and prowlers can remedy this problem simply by installing lights on a motion detector.
Last year, over 400 cities across the world celebrated Earth Hour by turning out the lights for one hour. Google's page went to a black background (cute!) and the lights which illuminate the San Francisco Bay Bridge were turned off. (Not the ones that mark the bridge's edges, or the ones that light up the bridge deck for drivers - just the decorative lights.)
Turning off unnecessary lighting, and using more efficient lighting that puts the light where it needs to go, is a perfect example of a win-win-win solution. The first "win" is the money saved by using electricity more judiciously. The second "win" is in the overall impact on climate change, by using fewer resources to achieve the same results. The third "win" is for astronomers, migrating birds, and anyone who has ever looked up at the sky.
A darker sky is a better sky, for everyone.