Light and dark

By Rae Wear

At the first public meeting I attended on arriving on Coochiemudlo eighteen years ago, the subject of Island lighting arose.  As newcomers, we listened as both sides made their cases. One group argued for an increase in permanent street lighting, largely on safety grounds.  In response, a long-term resident stood up and said, ‘just carry a torch.’  The arguments for that position are strong.

The behaviour of birds, plants and animals has been shaped by natural light — sunrise, sunsets, the moon, the stars and periods of darkness. Artificial lighting destroys these natural patterns and disrupts foraging, breeding and migrating behaviour. Turtles, for example, are profoundly affected by an excess of artificial light. Nesting turtles and hatchlings are easily disoriented by artificial light. Hatchlings navigate from their beach nests to the sea by heading towards the lightest horizon, which naturally occurs at sea. Artificial light can disorient them and leave them stranded. Shore birds, too, are disturbed by artificial light. They prefer to roost in darkness and often avoid lighted feeding areas that would otherwise be suitable. Even plant growth can be affected, when the natural alternation between day and night disappears.

The wonders and benefits of a dark sky

It’s not only birds, plants and animals that benefit from a reduction in artificial light. Light pollution from big cities means that residents never normally see the stars. According to the Brisbane Astronomical Society, Brisbane is one of the most light- polluted areas in the Southern Hemisphere. Brisbane’s sky glow reaches us here on Coochiemudlo but it is still possible to enjoy finding the Southern Cross and other constellations from the Island. We are also fortunate that the Emerald Fringe provides a buffer against a lot of light spilling over to the beach and shore, allowing us to enjoy the moon and the stars.  Increasingly, Dark Sky organisations are working to conserve and restore dark sky places around the world. The Sunshine Coast hinterland, for example, is considering a proposal to become a Dark Sky Reserve.  

Not only does the natural environment benefit from a reduction in lighting, but there are substantial savings in money and energy. Dark Sky International suggests that we only turn lights on when they are needed, that they should be targeted to where light is required, without unnecessary spillover, and that lighting should be set at the lowest level of brightness necessary. Controlled timer and motion lights are highly recommended and warmer colour lights are also preferred, where possible. 

A torch, rather than an increase in permanent lighting, seems like a good idea.