Light pollution occurs in areas all over the world where artificial lighting is placed to light the night. Excess light shines into the atmosphere and creates a glow that diminishes visibility of the natural night sky. Approximately 2.2 billion dollars in energy consumption is wasted annually from light shining directly into the sky. Inefficient use of technology and the resulting light pollution is a growing concern.
Effects on Human Health and Wildlife
Daily light-dark cycles are necessary for maintaining human health and wildlife activity. Artificially lighted areas create light pollution which masks these cycles. Artificially lighted areas disrupt behavior, reproduction, nourishment cycles and predator-prey relationships in wildlife. In Yellowstone, this manifests in negative impacts to long-eared bats, blotched tiger salamanders and various songbirds. In humans, excessive light levels are known to impact behavior, melatonin production, sleep patterns, and may contribute to the development of various types of cancer.
Yellowstone by Night
Most of Yellowstone is free of artificial light. However, in developed areas throughout the park there are more than 5,000 light fixtures. In the past, visitors often encountered bright light fixtures illuminating streets and buildings in the park making it difficult to view the natural night sky. Now, light fixtures are being replaced with low wattage, energy efficient, fully shielded fixtures that direct light only downward. Currently, only 46% of light fixtures are on at night and 75% those are fully shielded; helping to further preserve nighttime wilderness.
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