What is light pollution?

GLARE: Light shining directly into your eyes, causing discomfort and reducing your ability to see.

LIGHT TRESPASS: Light falling where it is not needed or wanted--for example, spilling over onto your property or into your home.

WASTE: Lighting that’s on when it needn’t be; lighting that’s excessively bright; unshielded lighting that spills out and upward instead of being directed at its intended subject.

SKY GLOW: The result of upward-shining light, which is reflected off moisture and dust particles in the atmosphere to illuminate the nighttime sky and wash out all but the brightest stars. See image above.

Why should it be curbed?

Wasted light wastes money. It has been estimated that a third of outdoor lighting spills out and upward, totally wasted; a conservative calculation of the cost comes to around $4.5 billion annually. Added to that figure is the waste from excessively bright lighting and the 100% waste from lighting that’s on when it needn’t be. You are paying the price through higher taxes for public lighting and inflated costs for consumer products and services.

Wasted light causes unnecessary air pollution. Most electricity for lighting is generated by burning coal and oil. Every year this process spills out billions of tons of sulfur dioxide (an ingredient of acid rain), carbon dioxide (a greenhouse gas), and smog-causing nitrogen oxides.

Wasted light squanders irreplaceable natural resources. The annual waste just from unshielded lighting has been estimated at more than 8 million tons of coal or 30 million barrels of oil.

Light pollution creates unnecessary hazards. Glare from bad roadway and roadside lighting that blinds a motorist, even momentarily, can be fatal; older Americans are particularly at risk. The eye takes time to adjust from excessive brightness (common at gasoline service stations) to less bright areas (as you pull out onto the darker roadway). Impaired vision during such “transient adaptation” can pose hazards for pedestrians as well.

While outdoor lighting may reduce the fear of crime, it can also attract criminals, illuminating their tasks and creating deep shadows to hide in. In 1977 and again in 1997, investigations by the U.S. Justice Department concluded that there is no meaningful evidence that street lighting affects the level of crime. Light pollution can harm plants and animals. All earth’s creatures have evolved over thousands of years by adapting to a world that is dark at night. The loss of true darkness can alter the growth cycle of trees, weakening them and making them more susceptible to disease and severe weather. Birds, fish, frogs, moths, and plankton are just some of the animals whose behavior has been shown to be affected by increasing nighttime light--often with disastrous results.

Sky glow is obliterating the stars. Satellite images show one huge blob of light running down the Eastern seaboard almost solidly from Maine to Virginia; the epidemic of wasted uplight has become so severe that two thirds of Americans can no longer see the Milky Way. A dark sky full of shimmering stars is a thing of great beauty--a source of inspiration and information to diverse cultures across the centuries. Shouldn’t we preserve it for ourselves and for our children? Source of above: SELENE