These days we often hear about pollution in its various forms but another form of pollution – light pollution - is a problem which many people are not aware of. Light pollution is gaining increasing attention from astronomers, environmentalists and people who wish to reduce energy consumption.
What is light pollution? The International Dark Sky Association defines it as the inappropriate or excessive use of artificial light. There are four components of light pollution - glare, skyglow, light trespass and clutter.
Glare is excessive brightness that causes visual discomfort and skyglow is the light halo over inhabited areas. Light trespass occurs where light falls where it is not intended or needed and clutter happens where groupings of light sources produce a bright, confusing effect.
The Dark Sky Association points out that much outdoor lighting used at night is inefficient, unnecessarily bright, poorly targeted and not properly shielded which means it is spilling into the sky rather than doing the job it was intended for. This of course means that much of the electricity used to create it is being wasted.
According to a 1916 study, 80% of the world’s population lives under skyglow. Major population centres like the United States and Europe are heavily impacted. There 99% of people are unable to experience natural night.
While skyglow away from our major cities is not as bad as in Europe, the US and Asia, we are still affected by it. Even in comparatively small population centres like Grafton we do not see the night sky in all its glory. If you visit areas in western NSW away from towns and look at the night sky on a cloudless night, you are likely to be amazed at the clarity of the heavens and immense number of stars.
Light pollution is not a concern merely because of aesthetics and the need to conserve energy. It disrupts ecosystems and wildlife. Plants and animals depend on the daily cycle of light and dark to govern life supporting behaviours such as reproduction, nourishment, sleep and protection from predators.
This article was originally published in the VOICES FOR THE EARTH column in The Daily Examiner on September 9, 2019