The Blackall Range, with its stunning night skies, is a haven for stargazers and a reminder of the wonders of our natural world. However, the glow of artificial light is increasingly encroaching on this natural darkness, posing a significant threat to the diverse wildlife that calls this region home.
Light pollution, the excessive or inappropriate use of artificial light, is a growing global concern. It not only diminishes our ability to enjoy the night sky but also has profound impacts on wildlife.
Light pollution comes in three main types:
- Sky glow:
The rusty orange haze cast by the massed lights over a wide area. - Glare:
Direct light from sources like streetlights, security lights, car headlights, and even neighbouring windows. - Light trespass:
Light that shines where it’s not wanted, such as a streetlight beaming into a bedroom or the annoying bright light from a neighbour’s badly adjusted security light.
Sky glow washes out the night and blots out the stars, while local sources are more prone to ruining night vision. Under dark skies, you can see stars down to magnitude +6.5 with the naked eye, but light pollution can cut this to just a handful of first-magnitude stars. Another common casualty of light pollution is the pale band of the Milky Way, the river of stars that stretches high across the autumn skies.
While specific, quantifiable data on light pollution increases on the Sunshine Coast over the past 5-10 years are not available, this is what we can infer:
The Sunshine Coast has experienced significant population growth in recent years. This increased development and urbanisation has contributed to increased light pollution. More houses, businesses, and infrastructure mean more artificial lights. As the region expands, development has encroached on previously dark areas, leading to increased light pollution in those locations.
A Recent Study Paints a Grim Picture for Astronomy
A recent study from 2023, reveals that over 80% of the world’s population lives under light-polluted skies, with the darkness diminishing at an alarming rate of 10% each year. The rise of LEDs, particularly those emitting blue light, worsens the situation. These lights scatter more widely in the atmosphere, interfering with telescope observations.
Additionally, satellite megaconstellations like SpaceX’s Starlink further obstruct the view by reflecting sunlight, with 5-10% of these artificial stars constantly whizzing across telescope fields. (StarLink has launched over 4600 satellites for its StarLink constellation alone). There are believed to be around 400,000 satellites in low orbit around earth. The upcoming Vera C. Rubin Observatory (formerly known as the Large Synoptic Survey Telescope) in Chile, designed to revolutionise cosmic exploration, is predicted to discard 40% of its images due to satellite trails. Even naked-eye observations are affected, with half of twilight-hour images potentially compromised.
While newer LED lights are more energy-efficient, they emit more blue light. These new lighting technologies have a greater impact on wildlife and contributes to sky glow.
Anecdotal evidence from local astronomers and observations by residents suggests changes in the brightness of the night sky due to light pollution.
How Light Pollution Affects Wildlife
Animals have evolved under natural cycles of light and darkness. Artificial light disrupts these cycles, leading to a range of negative consequences:
Disorientation and Death
Many nocturnal animals such as gliders, bats and possums rely on darkness for navigation and hunting. Artificial light can disorient them, leading to collisions with buildings, vehicles, and power lines. Sea turtles, for example, are drawn towards the brightest light on the horizon, often leading them away from the ocean and towards certain death.
Habitat Loss
Artificial light can alter the behaviour of animals such as owls, making them avoid areas that were once safe and essential for their survival. This can lead to habitat fragmentation and reduced access to food and shelter.
Reproductive Disruption
Artificial light can interfere with the breeding cycles of many animals. Birds may start nesting too early, when food is scarce, or may abandon their nests altogether. Some insects are attracted to lights, disrupting their mating rituals and reducing their populations. Some frog species use visual cues, such as moonlight, to trigger breeding behaviour. Artificial light can disrupt these visual cues, leading to decreased breeding activity.
Physiological Impacts
Constant exposure to artificial light can disrupt the natural hormone cycles of animals, affecting their growth, development, and overall health. For examples, possums and gliders rely on melatonin, a hormone that regulates sleep-wake cycles. Artificial light can suppress melatonin production, disrupting their natural rhythms and potentially affecting their reproductive cycles, immune function, and overall health.
Humans are also affected by light pollution, with research demonstrating its disruption of the circadian rhythm, leading to difficulties falling asleep. Furthermore, multiple studies have linked light pollution to an increased risk of obesity and depression.
Minimising the Impact of Light Pollution
We can all play a role in reducing light pollution and protecting our wildlife. By implementing these simple steps, we can preserve the natural darkness of the Blackall Range and ensure a healthy future for the wildlife that depends on it.
Responsible outdoor lighting is:
- Useful:
a. Employ lighting only when necessary.
b. Every light source should serve a clear purpose.
c. Carefully consider how lighting will impact the surrounding environment, including wildlife and their habitats. - Targeted:
a. Direct light precisely where it’s needed.
b. Utilise shielding and careful aiming to confine the light beam downward and prevent unnecessary spill. - Low-level:
a. Maintain the lowest light level required for the intended purpose.
b. Be mindful of surface reflectivity, as some surfaces may reflect more light upward than intended. - Controlled:
a. Employ lighting only when it’s required.
b. Utilise controls such as timers or motion detectors to ensure efficient lighting use, dimming when possible, and automatic shutoff when not needed. - Warm-coloured:
a. Prioritise warmer-coloured lights whenever feasible.
b. Minimise the use of shorter wavelength (blue-violet) light to the absolute minimum required.
Protecting our night skies is crucial for the health of our entire ecosystem, extending beyond the aesthetic appreciation of stars. Our actions today will have significant and long-lasting consequences for future generations. We have a responsibility to ensure that not only our children and grandchildren, but future scientists, environmentalists, ecologists, artists, storytellers, and those who value cultural connections to the night sky, inherit a world with dark skies.
Additional Information:
Australian Light Pollution website
https://www.dcceew.gov.au/campaign/light-pollution
National Light Pollution Guidelines for Wildlife website
https://www.dcceew.gov.au/campaign/light-pollution
Dark Sky Principles for Responsible Outdoor Lighting
https://darksky.org/resources/guides-and-how-tos/lighting-principles/
Home Lighting Assessment
https://darksky.org/get-involved/home-lighting-assessment/