Light Pollution

Light pollution isn’t just an annoyance, it can have a host of negative effects that are often overlooked.

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The Effects of Light Pollution

Seeing Stars
Light pollution affects our ability to see stars in the night sky. In many cities it is impossible to see the majority of stars, including most of the milky way. This makes it hard for astronomers of all kinds to do any kind of work in or a near a city. This is one of the reasons astronomers are forced to work high on mountains and in the middle of deserts.
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Effects on Wildlife
Light pollution actually has an effect on wildlife.

*Searchlights and flares on oil platforms can “capture” birds. They keep circling the light source until they run out of energy and fall.

• Insects cluster around light sources at night and bats are now used to following them for easy food. This has had adverse effects on other bat populations that are unable to do this as effectively.
  *Many types of nocturnal prey now find less food because they must forge more cautiously because they are no longer protected much by what’s left of the dark.
  *Artificial light has been proven to effect bird eating and migration habits, causing them to migrate early and arrive to adverse conditions.
  *Sea turtles search for beaches with little light to lay their eggs and go to the same beech or generations. The light pollution may confuse them and they often end up on roads.
• Frogs have been shown to inhibit mating calls at night when there is too much light, leading to lower reproductivity.
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  Light pollution doesn’t just mess with wildlife, it also has a negative impact on us.
  It can effect the circadian clock, leading to all kinds of biological and psychological effects, including:

*Hormone production
*Cell production
*Higher likelihood of depression
*Higher likelihood of insomnia
*Increased risk for cardiovascular disease
*Increased risk for some forms of cancer

• It has changed our sleep schedule. (From two four hour blocks to a solid block)
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Cost of Light Pollution

Light takes electricity to produce. Most of this electricity comes from coal. This means it both has a cost in money and in environmental impact. The light that is wasted is the problem. As much as 35% of all light produced is wasted due to unshielded light sources allowing it to go into the sky. This amounts to about 0.5 kilowatt hours per household per night. This wastes about 3 billion dollars a year total (in the US).This amount of power leads to 15 million tons of CO2 to be released every year.[5]

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How You can Help

Shielded lighting is one simple change with a major effect. It will reflect back the light that would go into the sky. The reflected light would make the light source seem brighter. That means it is possible to use lower energy light sources and have the same effect.

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Another way to help with light pollution is to turn your outside lights off at night. Many people keep these lights on to deter crime. There is actually very little evidence this works, in fact you are more likely to get robbed in a brightly lit alley than a dim one. This is because lights make the target easier to see. [6]

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