Architects, are you polluting the night sky?
In recent years, the ‘dark-sky’ movement has gathered momentum as a possible panacea for the detrimental impacts of illuminating the night sky with too much artificial light. The dangerous repercussions of light pollution are many and varied.
Nocturnal animals’ breeding and migratory habits are being gravely disrupted. For humans, the physiological impacts of light pollution can lead to insufficient melatonin — the hormone that helps us sleep and regulate cortisol levels. Meanwhile, researchers are struggling to observe and study the night sky.
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Scientist Dr Kellie Pendoley, founder of Pendoley Environmental, has spent 30 years studying the impacts of light pollution and helped draft the federal government’s National Light Pollution Guidelines for Wildlife. Thanks to recent updates, the guidelines now aim to protect all species, not just those referenced in the Environmental Protection and Biodiversity Conservation Act. “Light pollution is having really serious impacts on wildlife and on human health,” Dr Pendoley says. “Technically, light is a form of radiation but it’s never been recognised or managed that way.”
According to Dr Pendoley, there are countless reasons to contain and control light. “Light pollution also impacts our heritage,” she explains. “First Nations people are the oldest astronomers on earth and they tell their stories through the stars.
“Limiting the visibility of stars, limits the ability of First Nations people to share their stories — that’s an important cultural connection we need to preserve.”
According to our electrical engineer Toby Murdoch, everyone working in the built environment has a part to play in minimising light pollution. “Regulators, clients, architects, lighting designers, and contractors should all be working in unison to bring about real change,” Toby says. Meanwhile, he’s put together a list of four simple yet effective ways to reduce light pollution.
1. Select the right light fittings
For lighting large outdoor areas, like sporting stadiums, Toby recommends ‘flat-tilt’ asymmetric floodlights to ensure the light lands where it’s most needed.
“Traditional floodlights only provide symmetrical lighting so the fitting has to be tilted to target the area you wish to light,” Toby explains. “A significant portion of that light will go above the horizontal plane — directly into the sky.” The result? Wasting energy and unnecessarily polluting the night sky.
Closely monitoring ‘light spill’ (ie sending light to locations where it’s not needed) and ‘light glare’ (ie light that causes discomfort or impedes people’s ability to navigate a site) is, of course, essential.
2. Minimise blue-spectrum lighting
Toby reflects on the emergence of LED lighting and laments its impact on light pollution. “When LED lighting was first introduced, the energy efficiency of bright-white light was considered far greater than warmer colours,” he says. Unsurprisingly, that efficiency/affordability led to increased popularity for white-coloured LEDs.
But white light is problematic because it has a degree of blue spectrum within it. “Any light source that contains an element of blue will likely be more reflective than warmer colours,” Toby says. The result? White LEDs create significant “sky glow”.
Dark-sky advocates, and Toby too, would prefer designers opt for LEDs with amber and/or warm-white colours that are less reflective and cast less “sky glow”.
3. Adjust illumination
Toby encourages architects to stay abreast of emerging technologies designed to help minimise wasteful lighting. He points to street lighting to illustrate the power of advancing tech.
“Motion sensors are now available that can brighten street lighting as you reverse out of your driveway — then incrementally brighten the next sequence of lights before you approach them,” Toby says. That kind of technology can take a light from 20% illumination to 100%, as and when required. “That’s up to an 80% energy saving but also limits unnecessary light pollution from adversely impacting surrounding wildlife,” Toby says.
Streetscapes aside, Toby urges architects to think about simple strategies such as automatic late-night dimming for facades and exterior spaces that may not require full illumination from dusk till dawn.
4. Challenge convention
“We have a primal fear of the dark,” Toby says. He’s not convinced that fully illuminating large outdoor spaces always deters/repels troublemakers. “I’d like to see architects press their lighting designers to look for alternate ways — that don’t rely on excessive light pollution — to provide passive surveillance for their projects.”
Toby acknowledges the reticence of design teams to pull back on lighting. “I think sometimes we are scared of not providing enough light, so we provide too much! We need to be braver and embrace the shadows,” he says.
According to Toby, landscape architects take little convincing when it comes to designing with dark-sky top of mind. “Professionals from within that discipline are well informed and receptive to challenging the status quo when it comes to lighting,” Toby says.
Dr Pendoley works with design teams from around the globe, sharing methods of measuring, monitoring and modelling light — not just on a local level but on a landscape scale up to 100 kilometres away. “I encourage every architect and designer to look beyond their building’s footprint — light scatters into the atmosphere and that is what creates biological implications.”
Restraint is a key theme in Dr Pendoley’s recommendations. “Obviously, the more lights you have, the more energy you burn and the more greenhouse gases you emit,” she says. “That’s a basic principle that’s easily understood when advocating the ‘less is more’ approach.”
Dr Pendoley is hopeful and says she has cause for optimism, especially when she sees lighting-design master plans that limit artificial light. “When it’s well designed, lighting can be both beautiful and muted. I’ve seen exemplars around the globe that prove built structures can be illuminated in subtle ways that make them look and feel elegant. Big, bright lighting comes at a cost, aesthetically and environmentally.”
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