Light Pollution

Dark Skies


Example of light pollution from a floodlight without shielding.

From bird feeders to firefly chases, many people like to experience wildlife in their backyard. But they are blind to the impact artificial light has on wildlife.

Our modern society has become used to more and more lights brightening our nighttime environment. But bright light throughout the night can have calamitous effects on animals, insects, plants, and also health of humans. Many species need darkness to survive and thrive.

Light Pollution Has Far-Reaching Consequences

Here in Gallinas Valley many of us live very close to nature, and our light pollution produces a continual state of “twilight” in the habitats around us.

This twilight affects the mating habits, feeding patterns, navigational skills, and circadian rhythms (24-hour cycle in the biochemical, physiological, or behavioural processes of living entities) of mammals, birds, amphibians, reptiles, and insects.

Bright outdoor lights disrupt the migrating, eating and mating of nocturnal animals. Unwanted light trespass into surrounding natural areas not only disturbs but can also attract nearby wildlife.

Even certain trees are induced to shed their leaves out of cycle, disrupting the basis of the food chain. There are long term impacts of artificial light at night on ecosystems.

It has recently been shown that light pollution also contributes to smog. NO3 is a compound destroyed by sunlight which normally builds up in the darkened sky. It neutralizes some of the NOx that foul daytime air with ozone (O3). This nightly cleansing action isn’t as effective as it could be — because nitrate radicals are being destroyed by light beamed into the sky by outdoor lighting on the ground.

The good news is:

  • California has some of the strictest outdoor-lighting regulations
  • Federal stimulus money supports US Dept of Energy and EPA campaigns for LED lighting


Smart Lighting – Protect the Environment and Save Energy

There are many persuasive arguments against light pollution and in favor of smart lighting (in particular with LED lights) Don’t just do it for our environment, there are other great reasons to use smarter lighting:

  • Shielding a lamp usually requires a lesser wattage bulb, thereby saving energy
  • Save money (less energy consumption = less cost)
  • Shielding reduces glare (which can be blinding) allowing you to see lit areas better and more naturally
  • Shielding produces fewer harsh shadows (where someone can hide).
  • Shielding a light improves the visibility of the night sky (hello Milky Way)

You Can Help
To Restore Environmental Balance: Use Smart Lighting

If you have installed outdoor lights on your property, and if your lights are a bit too bright and they are shining in out onto fields, marshes, or other open areas, then perhaps they can be re-directed onto the ground where they will do the most good.

  • Purchase Fixture Seal of Approval (FSA) approved outdoor light fixtures that shield light, such as the Glarebuster
  • Use light only WHERE it is needed with well-designed fixtures that put light onto the ground instead of sending it into the sky
  • Use light only WHEN it is needed by using timers and motion sensors
  • Use only as much light as needed for safety and security
  • Use energy efficient lighting with less scatter and glare
  • Use HPS (High Pressume Sodium) and LED type bulbs (incandescent bulbs squander 90% of their electricity as heat; CLFs contain mercury and must be disposed of as toxic waste)

coverngm200811_us_sized_imageFurther Information

International Dark-Sky Association website (THE Light Pollution Authority)

Effects of Artificial Light at Night on Wildlife (PDF)

Five Ways to Bring Back The Night

National Geographic Light Pollution Special

Understanding Light Pollution (Cape Cod Astronomical Society)

It’s All About The Lighting (Wall Street Journal)