Feature
Good night
by Rebecca Greatrex
Come over to the dark side, say anti-light-pollution advocates – the view is so much better
Seen from outer space, the dark side of our planet glitters with millions of lights. They shine so brightly that cities, coastlines and countries are clearly identifiable. Even New Zealand, with a relatively low population, glitters more like a small constellation than the Pacific’s triple star.
It’s difficult to believe in power crises when streetlights continue to sparkle across our urban landscapes. And although they might look pretty, as though the stars have fallen to Earth, the reality is more ugly. It’s called light pollution and it has a direct detrimental effect on the quality of the environment. It also has an adverse financial impact on ratepayers and the economy in the form of wasted energy: sending all that electricity into space is very expensive – in the US, the cost is estimated at between $US1 billion and $2 billion every year.
In New Zealand, a study done in 2001 concluded that local government could save at least $2 million per year in energy costs, just by improving the energy efficiency of street lighting. The study was commissioned by the Energy Efficiency Conservation Authority (EECA) and investigated the street-lighting policies of more than half of the 73 territorial and local authorities. The report concluded that the energy costs of street lighting are at least $18.6 million annually and, since at least one of the larger local authorities did not respond to the survey, this figure is conservative. When network charges are added in, too, the cost jumps to $31 million. And, although the local authorities maintain residential and road lighting, the additional 36,000 streetlights alongside state highways and motorways are usually the responsibility of Transit New Zealand and were not included in the EECA study.
The cost of light pollution cannot be measured purely in financial terms, however. The aesthetic cost to city-dwellers all over the world is the loss of their view of the night sky, and the less tangible value of its reminder of our place and (in)significance in the cosmos.
Instead, the orange haze of light pollution hangs over every city, blotting out all but the brightest stars. Some might argue that this inability to stand beneath a natural dark sky and look up into the universe, sprinkled with brilliant stars set against the rich misty sweep of the Milky Way, is a spiritual loss. It’s a sad irony that a whole generation is growing up on the visual feast of space-based films and television shows, but is unaware of the awesome beauty of a star-filled night sky and the constellations that were so familiar and important to our forebears.
But awareness and interest in overcoming light pollution is growing around the world. In the UK, research by the Council for the Protection of Rural England (CPRE) found that during the 1990s, the amount of countryside with pure, dark skies was reduced by 27 percent. Earlier this year, CPRE and the British Astronomical Association launched a campaign to fight the problem. “We’re spoiling so much of the mystery and beauty and the wildness of the country,” CPRE president Sir Max Hastings told BBC Radio.
The International Dark-Sky Association (IDA) would agree. It was set up in 1988 as a non-profit organisation with the goal of “preserving and protecting the night-time environment and our heritage of dark skies, through the use of quality outdoor lighting”.
There are different approaches to overcoming light pollution and, happily, some of them combine both environmental and financial benefits. A common fallacy about lighting is that bigger and brighter equates to better and safer. In fact, excessively bright lighting makes much of the urban environment visually harsh. Instead of increasing security, shadows can seem even blacker, hiding rather than revealing hazards.
Sharp transitions between different lighting levels can leave us with reduced vision (known as transient adaptation) while our eyes adjust to the new lighting level. It was probably for this reason that the LTSA was not keen on power savings that could have been achieved by taking alternate streetlights out of commission.
The critical factor is good design, which ensures that light is directed only where needed. Consequently, a well-designed light fixture can consume less power. Visibility and safety are maintained or even improved – simply by using less light more effectively.
Check out the design of your local street lights. The odds are that they have a rounded dome hanging underneath. This is a typical semi-cut-off assembly that allows some light to escape sideways as glare and some to escape upwards as sky glow. If a full-cut-off fixture was used instead, the streetlight would have a flat bottom and shielded sides, thereby directing the light downwards. Glare is reduced and visibility is increased.
The IDA 2003 International Lighting Awards, announced in March, were given to lighting installations that used effective shielding and design techniques to achieve quality outdoor lighting. Recipients ranged from the Gentilini Ford Dealership in New Jersey in the US to the Hungarian National Railways – which has reduced the wattage on 16,000 lights by almost 50 percent through the use of fully shielded fixtures.
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