Losing the Dark – The Importance of Dark Skies to Astronomy, Nature, and Us
Dr. Mindy Townsend
December 8, 2024
Dr. Mindy Townsend is the Dudley Astronomer with Sienna College. She discussed the ways in which nighttime light pollution is impacting astronomy, nature, and humans.
Various types of light pollution, which include sky glow, glare, light trespass, and light clutter, are reducing the darkness of the night sky around the world. In the US, observations by citizen scientists have documented a 10.4% increase in light pollution per year on the Bortle scale, a ranking system for the darkness of a sky. This increase occurs primarily in urban areas, but has also been noted in rural areas.
Research has shown that sea turtles, particularly green sea turtles and flatback sea turtles, are attracted to artificial light. Artifical lights cause hatchlings to be vulnerable to predators and exhaustion because the young turtles don’t head for the ocean quickly. Artificial light also can affect the behavior of bats with different species responding differently to different wavelengths of light. Some species exhibit decreased activity under all lights, while others avoid orange, white, and green light, and yet other species showed more activity under artificial lights.
Artificial light can also alter the behavior of plants and trees. A 2016 study in the UK found the onset of budburst in various deciduous trees was affected by artificial light with early budding trees being less affected. The timing of budburst can have potential consequences on ecosystems. One example is the winter moth caterpillar’s relationship with the Penuncula oak. However, the effects of artificial light on plants and animals are not yet fully understood and requires further research.
Preserving dark skies is important for both environmental and cultural reasons. Light pollution has negative impacts on wildlife, particularly nocturnal animals. There are many challenges facing efforts to reduce light pollution and it’s not always easy or practical to make significant changes. Some simple actions that can reduce light pollution include turning off lights when not needed, directing lights to where they’re needed, and using warmer colored lighting. Some cities, such as Tuscon, and national parks are leading the way in reducing light pollution in order preserve dark skies for future generations.
Light pollution is a significant issue that needs advocacy and understanding from the community. Ways in which light pollution could be reduced or controlled include changing zoning codes and highlighting economic arguments for reducing light pollution that show it could save money for businesses.