This post is part of a series of posts to commemorate International Dark Sky Week (19th-26th April 2020), dedicated to celebrating the night sky. Our lighting practices don’t only affect astronomy – they can impact other important things too. I’ll dive into some of these, and a few things you can do to make a difference.
If an action is simple, within our reach, and can lead to the protection of the wildlife we share the planet with, we have a duty to take this action. By changing our lighting practices, we will take significant steps towards caring for and conserving the wildlife and environment of the planet we inhabit.
Artificial light generated and directed by humans can have detrimental effects on wildlife. The ill effects caused by artificial light are termed light pollution, and are as important to consider as any other type of pollution when we talk about conservation. Human efforts to light up streets and billboards at night, and any source of light that interrupts the natural day/night and lunar cycles, can wreak havoc on wildlife that depends on these cycles for important biological processes. Migratory birds, for instance, rely on moonlight and starlight to navigate, and can be thrown off course by bright city lights, directing them into cities, where they run the risk of fatally colliding with buildings and towers.
The consequences of light pollution aren’t limited to land animals – marine life is affected too. Moonlight is an important cue for some coral to reproduce, and when it is masked by city lights their internal clocks become asynchronous. Freshly hatched sea turtles, arguably the most threatened by light pollution, use the brightness of the sea to find their way to it. They need to be in the sea to survive, but many are misdirected by illuminated roads, and lose their lives.
Luckily, the things that we can do to reduce light pollution are simple, and the effects can be immediate. The simple act of turning lights off when not in use can make a world of difference. Lighting can also be designed to only shine where it is needed, preventing light spillage and interference with wildlife. Responsible steps further would be to lowering the intensity of the light used, and doing some extra research to select a frequency of light that doesn’t interfere with the surrounding wildlife. Sometimes a light isn’t even needed where we think it is – alternatives like reflective paint and luminous markers are effective replacements for night time.
Simple actions and careful consideration surrounding artificial light are not only useful for astronomy. They go a long way in preserving and protecting the beings we share our planet with.