Why dark skies matter

Thoughtful lighting design can protect cultural connections, biodiversity and human wellbeing while creating comfortable and safer places after dark. Last month, we hosted an event at MPavilion in Melbourne, organised by Stephanie Sirianni of Nature Collective. Stephanie brought together perspectives from ecology, First Nations knowledge and lighting design to explore a shared passion: why dark skies matter.

Sky Country: protecting Indigenous knowledge and connection

Kai Lane from Ecology & Restoration Australia, a proud Yorta Yorta and Barapa Barapa man, explained that for Aboriginal and Torres Strait Islander peoples, the night sky is more than a canvas of stars. It is a living archive of knowledge, culture and identity. The stars are woven into stories, seasonal calendars, navigation and spiritual beliefs, forming part of Sky Country, which recognises the sky as integral to Country and culture.

Constellations such as the Emu in the Sky, formed by the dark dust lanes of the Milky Way rather than by stars, guide seasonal activities including emu egg collection. The Murray Cod constellation is visible in the night sky, it signals that warmer weather has arrived and the river temperatures are rising. This indicates that the Murray cod are spawning and laying eggs, and acts as a warning that you are not allowed to catch or eat them during this time to preserve the species.

As light pollution spreads, however, this connection is fading. Urban glow and satellite trails obscure the stars, making it harder for communities to pass down stories and maintain cultural practices. Kai spoke of growing up looking at the stars and how, after moving to Geelong, he misses being able to look up into a truly dark night sky.

Preserving dark skies is not only about astronomy. It is also about respecting and protecting Indigenous knowledge systems that have thrived for tens of thousands of years. Through considered lighting design, we can help ensure future generations are still able to look up and see the stories written in the stars.

The hidden cost of light: impacts on Australia’s wildlife and ecosystems

Dr Jo Isaac, Principal Ecologist at Ecology & Restoration Australia, explained that light pollution is more than a nuisance. It is a growing ecological threat. Australia’s unique biodiversity, shaped by millennia of evolution under natural light cycles, is increasingly vulnerable to artificial light at night (ALAN).

Jo discussed the grey-headed flying-fox as one example. Unlike smaller microbats that use echolocation, grey-headed flying-foxes rely on excellent night vision and their sense of smell to navigate. High-intensity white lighting can disorient grey-headed flying-foxes and may increase their risk of colliding with buildings, powerlines and vehicles.

Growling grass frogs, which are listed as Endangered on the IUCN Red List, also depend on darkness. Males use distinctive, deep calls to attract mates between August and March. Artificial light can disrupt this process, with studies of urban frogs showing that high light levels may cause amphibians to shift, delay or reduce their night-time calling.

Little penguins, also known as fairy penguins, are nocturnal on land. Their eyes are highly sensitive and adapted to dim, natural lightscapes. Bright white light from torches, smartphones or infrastructure can disorient and disturb them.

The ripple effects can be profound. When one species is thrown off balance, entire ecosystems can suffer. Many affected species are pollinators or form part of wider food webs, so disruption can extend through the food supply chain. In Australia, where many species are already threatened or endangered, the additional pressure of light pollution could tip the balance.

Lighting and people: health, wellbeing and safety

I then shared took the stage and explained light pollution does not only affect wildlife. It affects us too.

Exposure to artificial light at night can disrupt our circadian rhythms, the internal biological clock that helps regulate sleep, hormone production and metabolism. Blue-rich light, particularly from LED sources, suppresses melatonin production that contributes to sleep disturbance, increased stress and longer-term health risks.

Poor lighting design can contribute to mental fatigue, irritability and reduced cognitive performance. In urban environments, excessive glare and poorly directed lighting can also compromise visual comfort and safety, making streets, pathways and public spaces harder to navigate. Ironically, over-lighting can reduce the perception of safety rather than improve it. Glare from unshielded luminaires obscures hazards and reduce visibility for drivers and pedestrians.

Designing a better response

Lighting design should be beautiful, functional and ethical. This is not about switching off every light. It is about using light thoughtfully and only where it is needed. Designers should:

• Direct light only where it is needed.
• Use responsive controls and sensors so lights operate when required and respond to people movement.
• Install shielded luminaires with correct optics to reduce glare and spill light.
• Select an appropriate colour temperature and spectra for the environment being lit.
• Consider luminaires approved by Australasian Dark Sky Alliance (ADSA) and Darksky International.
• Engage a lighting designer with experience in environmentally sensitive and dark-sky design.

By choosing thoughtful lighting design, we can protect Australia’s biodiversity while supporting human health, wellbeing and safety. As lighting designers, we have both the opportunity and the responsibility to shape how people experience their environments. Light is not just a tool for visibility. It influences health, habitats and our ability to see the stars above us.